engine revs

It's fine to ask 2 questions but you really need to ask them separately because it gets way to confusing to follow when posters are jumping from one issue to another.

I will address question number 1

A couple of things could be happening here. You could have an A/C compressor cycling on and off which will kick the RPMs up every time. You could also have a faulty IAC or dirty throttle body.

You may have a bad IAC ( idle air control) but try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

I have the same issue, if you unplug the MAP sensor (labeled boost sensor) it should run and idle smoothly, at least it does for me. I notice what happens is the map sensor would cause the fuel trims to spike really high, then the ecu would overcorrect the opposite direction causing a sudden stumble in the RPM's at idle. I have no idea if this is the same issue as you, but if you unplug the map sensor connector and then see if it stops, maybe that could point you in the right direction. Granted I have that issue and am having a really tough time figuring out why its doing that in the first place.. all i know is my car has the same idle drop symptoms and seems to work fine when I disconnect the map.. if that doesn't fix it then you can mark that off the list of things to check I guess.

Great addition to this thread! Please feel free to help out whenever you are on the site :)

Cheers, Ken

I have a Ford Probe and before i can make any adjustments to it i would like diagnosis of it. for one the car when one presses on the accelerater it seems to struggle to gain speed. im currently thinkin it might b the transmission. i regularly set the idle speed back to its normal rpm and it still does it. any one can help it woul b greatly appreciated.

I'm having a similar problem with my 95 SE. I'm also having an issue with it stalling shortly after I start it. It sometimes will go, and then stall after I'm driving. Repeatedly. Just recently started happening. I have roughlt 127 K Miles on mine, I believe a 2.0 engine. If anybody has any ideas what it is, please help us!!!

i also have had simular problems with mine. except with mine the car did NOT like to accelerate. i would turn onto a highway and press the gas pedal and the car would jerk and the rpms would almost max out. as it turned out it was in fact the transmission. it was skipping 2nd and 4th gear (my car is an AT) the repair shop had said that there suspected bolts broken inside the tranny and i needed a rebuild. we had done that and the car was fine for about a year until this time the car would decide that it just didnt want to drive. my step-father was taking it in to have the tranny looked at again and had to sit through a green light because the car would not drive. this time they said i needed a new tourqe convertor and since then the car has been good besides the new catalytic converter and a remaining issue with the check engine light telling me that the cat is causing prblems again. i had a hole in the cat before and had to get a new one, but now we are thinking that it is an O2 sensor or possibly the 2nd cat by the manifold. which i did not know that this car had two cat convertors. and my probe does only have 66,000 miles on it. way too many problems for that low of miles. one thing that i have learned from researching the cat it is that if they are clogged they can affect performance. this is just a guess, but it might be worth, and cheaper to start, looking into. and actually my car has stalled on me once while driving and i still have not figured out that one, especially since my idle is fine. but i do hope that by giving you the history of my car and symptoms help you in any way. i know its a lot but maybe there was something in here of use to you guys. thanks!

Engine Mechanical problem
1993 Ford Probe 4 cyl Front Wheel Drive Manual 150k miles

Ever since I changed my water pump my car will not run right. I had messed up the timing of the engine while doing it so I took everything back apart and fixed the timing of the engine. I have even taken it back apart to re-check it and it is exact. After fixing the timing the first time my car ran very badly for a week. Loss of power, bad gas mileage, very sluggish. I thought it was timing still so that is when I re-checked it. I noticed a motor mount ground that I over-looked. I put it where it needs to be and the car started again. It will not go past 200 rpms. I have a new distributor and I was trying to set the ignition timing but first it says to make sure my idle speed is alright. Here are the things I have done.
-Spark test (jumps gap)
-Fuel pressure test
-Compression test
-Timing of engine (it is exact)
-New spark plugs
-New fuel filter
-New ignition coil
-New plug wires
-New air filter
-Cleaned MAF sensor
-Cleaned IAC valve

I have removed a SPOUT connector to set the ignition timing and idle speed. I have it at TDC on the compression stroke with the rotor on #1. I tried to adjust the idle speed with the screw and it didn't affect it I also opened the throttle manually with my hand and the engine doesn't even surge. Even i press on the gas it barely goes up not even 50 rpms. I can feel exhaust out the back as it is sputtering at 200 rpms or less. I have a chilton manual that I am going by to set the ignition timing. I have the disty in the relative area where it needs to be but I have no completed the ignition timing since the idle is messed up. I am stumped to what is the cause of this. Something is holding it back somehow. My car ran fine until I changed the water pump but I couldn't drive like that obviously. Somewhere in between something has messed up and I can't figure it out. When the car ran bad for a week then quit, I figured the distributor went out on me which is why I have a new one. Also, my car does not give any codes anymore. The only one it did before the codes were cleared was CID failure. This is why I also replaced the disty. The ignition module and crank and cam sesnors are built into the distributor.

May have been sold a bad distributor, go back and get another one...

Hi
What method did you use to determine No. 1 cyl at TDC on compression stroke? what was results of compression test? 2.0L or 2.2L?
Let me know
Thanks for donate

For TDC, I lined up the marks on the cams like I did when I was doing the timing of the engine and I could also feel pressure in that spark plug hole. It is a 2.0L. For the compression test I was getting about 190psi in all 4. No major differences.

Belt on as in diagram?

Does distributor look like diagram?

Put timing light see where it is

Yep, the timing of the engine was exactly like that, i made 100% sure the marks were perfect. I've not yet hooked up a timing light because my book says to adjust the idle speed first. I haven't bought one yet because I didn't want to waste money since I couldn't get past the idle speed.

Engine Performance problem
1997 Ford Probe 6 cyl Front Wheel Drive Manual 156000 miles

When I'm at a stoplight my car will start revving on its own, when in gear and the clutch is let up car will then stall.. occasionally the car will not start unless I hold the accelerator to the floor.. I have replaced the cap & rotor, plugs & wires, also the intake and connected the disconnected vacuum lines problem still occurs????

Did TFI module come with new Dist? have you tried moving dist around a bit to see oif things improve?

Have you checked the fuel pump pressure? Has the check engine light come on?

The ignition module for my car is built inside of the disty....which is why I got a new one. The modules are likely to burn out on these probes. I did try and move the disty back and forth... I'd say there is just one sweet spot with a centimeter I could move it back and forth in between to where it will start.. Any movements past that sweet spot the car won't even start. When I have the disty in that spot, I have to pump the gas while cranking to even get the engine going. Sometimes it won't idle on it's own... The RPMS will go too low and it will die if I don't have my foot on the gas.

my check engine light has been on, I had it checked, I got a code for the cat, an egr valve, and a temp sensor disconnect. I haven't gotten the fuel pressure checked, I did however order a new fuel pump which I have plans to replace along with the fuel filter sometime this week.. Do you think that could be my problem?

Check firing order see diagram thinking dist is 180 out

It could be if the pressure was low, but you have a list of other things that could be causing the problem. Rather than the pump, I would be checking the EGR to make sure it is working properly and checking for vacuum leaks that can cause an idle problem.

I have aligned everything to TDC with the marks on the sprockets. I have taken pictures of the sprockets with the marks from both sides and a picture of the cam lobes. This is the way I had set it up before and the disty rotor still is on #1. My firing order is 1 3 4 2. Please take a look from the links. The image uploader on this site wasn't working for me.

Check out dist cap order all looks good in pics

Idle RPM seems to fluctuate but most of the time is over 1000 RPM (usually up around 1500 RPM). It can and does range anywhere from 1700 RPM to a low of say 300 RPM but as I say the majority of the time over 1000. Doesnt seem to be any rhyme or reason to it. One shop told me it could be the throttle body sensor (did he mean throttle position sensor?) and /or the throttle body itself. Another shop said this was wrong; the only thing a defective throttle position sensor will do is cause your car to stall! And what does the idle air control valve do? Could this be the problem? Someone else said something about vacuum lines. Any help appreciated. Thanks very much.

Bruce

yep, cap looks exactly like that, made sure the wires were all going to the right places.... i'm stumped

Go to this link for more information:https://www.2carpros.com/articles/engine-idles-too-high

Me too from what you say this car should run something got to be wrong with belt timing. when belt went back on and tensioner in place did you hand turn engine 2 revolutions and recheck all marks line up?

yes i double checked everything to see if it was still good to go... when i had the car running very badly before... i had done the timing but the camshaft sprocket marks were kind of pointing down towards each other rather than straight across, but that's just the way the engine fell by itself, this time i used a cam locking tool to align the sprockets straight across like the book says... as you can see the marks definitely look aligned on the camshaft sprockets, and i made sure the crankshaft was right on, there is a little groove that lines up w/ a mark

Check for an exhaust restriction, converter or muffler may be plugged, EGR stuck open. 190 PSI= timing is good. Check for stored codes, and fuel pressure.

i can feel exhaust coming out the back normally i'd say... what is the easiest way to test if the egr valve is stuck open? i'm going to list all the codes i've ever had before i cleared them...this is before i replaced anything...

eec-iv 3 digit codes:

116 Out of range Engine coolant temperature sensor (ECT)

121 Outside range throttle position sensor
(TPS)

159 Outside range mass air flow sensor (MAF)

214 CID circuit failure

...i had cleaned the MAF sensor and the iac valve... so i figured those 2 codes showed up because i had disconnected some things... i replaced the disty cause of the 214 code..

Engine Performance problem
1994 Ford Probe 6 cyl Front Wheel Drive Manual 357000 miles

Engone was running reasonably fine this fall, I had some clutch work done, then winter rolled in with colder temperatures.

Now When first starting and often while running, the engine will idle at varying speeds between 1200 and 1800 rpm. Occasionally when the engine has warmed up, the idle will return to normal.

What about the TPS? If this is bad, PCM wont know where the throttle is...test it with an ohm meter, needle should move smoothly as you move the throttle from closed to fully open. ANY jerking and it needs to be replaced. ECT is cheap, but acts as the choke, so replace that anyway. Have you rechecked the codes now? If MAF is still showing, the cleaning didnt work, and it should also be replaced. It controls fuel injector pulse width.

check your throttle body and throttle plate, clean it real good and see what happens. that may clear it right up, also check for small vacuum leaks, if this does not fix your problem then get back to me

i check the voltage of the tps and w/ it closed its about .9 volts and with it open it goes all the way up to about 4.5 volts.... i checked codes and i still get the TPS code, but that came on as soon as i unplugged it... that's why i think it came on last time i unplugged it... there are no other codes that show... i tried to remove the ECT sensor to test it, but i don't have the right socket so i need to go find one... would the ect sensor cause it to do what it's doing? the first thing that happened to me was my water pump going out on a 500 mile drive, so i drove about 250 miles having to stop every 15 minutes to refill my radiator

your head gasket is blown

what are the different ways i can test to see if this is true? it seems like a major job. i have done a compression test with 190 psi in all cylinders.. when it was running, i never noticed any smoke coming out the exhaust or smells and my oil looks regular.....

Get a block test kit at the parts store, this tests for the presence of hydrocarbons in the antifreeze, pressure test the cooling system, and compression leak down test are all ways to find out. Also any foam or bubbles in the radiator? Coolant is dissapearing with no leaks visible?

My mothers ford probe 93 gt 6cyl will suddenly either drop idle or rev like crazy. She has recently changed the front o2 sensor and found same problems still occuring. Any suggestions to make her life a little less stressful? Please help... :o

Don't know if this is in any way similar to the potential throttle problem i reported on my escort diesel on 3/4 which remains unfixed but a local gararage (who couldn't get to the root of the problem) thought it might be a fuel pump problem i.e. where some flap or other gets stuck open and causes the engine to race away. Sorry thats a bit non-tech but thought it worth mentioning.

so far i have tested for hydrocarbons and i'm all good there. no hyrdocarbons

i have recently started the engine and i tried to let it warm up a bit... the engine surged from about 200rpms to 1000 rpms just for a second, then back down then my car gave a code ( i was in diagnostic mode)

412 Engine speed during self test too low

i also had another code later on that i do not understand

522 Neutral/drive switch (NDS)

these are from the eec-iv tests

POWERTRAIN CONTROL MODULE (PCM) Ground Circuits 1. Using a DVOM, check for continuity to ground on PCM terminals No. 40 and 60. See Fig. 1 . Resistance should be zero ohms. If resistance is not zero ohms, repair open to ground. 2. Using a voltmeter, touch negative lead of voltmeter to a good ground. Touch positive lead of voltmeter to each ground terminal. With vehicle running, voltmeter should indicate less than 0.5 volt. If voltmeter reading is greater than 0.5 volt, check for open circuit, corrosion and loose connection on ground lead. Power Circuits Using a voltmeter, check for battery voltage between PCM terminal No. 1 (KAPWR) and ground. See Fig. 1 . Check for battery voltage at terminals No. 37 and 57 (VPWR). If battery voltage is not present, EEC power relay is not supplying power. See CIRCUIT TEST B in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. 522= Vehicle not in park or neutral during test?

IAC( Idle air control valve, it's bolted to the throttle body and clutch pedal position switch. Check email for testing proceedures.

i went through the steps for the IAC and it has good voltage coming to it and good resistance.. i could not get to the steps where it talks about the PCM and a breakout box... what is a breakout box and where can I get one?