check engine light is on?

What is the exact code numbers not code descriptions you have in the computer? I need you to use this guide to let me know.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

well i work nights which means i am at work. i have the paper at home I will have to get that to you later. thanks.

Your welcome please share the code with me when you can.

P0171 and P0302.

P0302 is misfire cylinder two, start here and this may solve all your problems. check comps, spark and vacuum leaks around this cylinder, start here.

So maybe the coil pack. hmm okay.

I do not know how to check for vacuum leaks. okay, I will just sell it.

Spray a little engine starter around the inlet manifold (engine running) and if the revs pick up momentarily there will be a vacuum leak there.

I would concentrate on the vacuum leak it could cause a lean miss and cause the p0302 code. When you sorry around use card spray when you get close to the let the rims can go up or down.

Number one fix for the p0171 is replacing the fuel filter. if yours has not been replaced in a while it would not hurt to do it. Second most common fix is intake manifold gasket leaking vacuum there is a starting point.

The check engine light comes on when the weather dips below -7 degrees celcius (or so). Usually when I hook it up to a diagnositc machine, I get one of the following codes: P0171 or P0174.

Today while driving to work, the light came on again. I hooked up the scan tool, and it came back with NO codes. The light was on, but no codes were present? How is that possible?

My O2 sensors seems to be working fine according to the scan tool (the graphs are not just flat, there is some movement), so what else could be causing the problme? Specifically, what could be causing those codes? Why does this only happen in the cold weather?

Help? Thanks.

PO171 - Fuel Trim System Lean (Bank 1)

PO174 - Fuel Trim too Lean (Bank 2)

Based on your description, my first guess would be the temp sending unit. It tells the computer ambient temp and coolant temp. From that, the computer determines how rich or lean to make the fuel mixture.

If that isn't the problem, check for an intake leak or other vacuum leaks.

Let me know what you find.

Joe

My check engine light came on, so I took it and pulled the codes. It said it was running lean on bank one and bank two. The guy at the shop told me since it was running lean on both banks, it is a bad mass air flow sensor instead of bad O2 sensors. I replaced the mass air flow sensor and he disconnected my battery to clear the code. I live in the houston area and emissions are important for inspection. I got my car inspected, then about a month later the check engine light came on again. I pulled the codes and again it is running lean on bank one and bank two. What should I do?

Have you checked for vacuum leaks?

I haven't heard any hisssing commonly associated with a vacuum leak. When I reset the code by disconnecting the battery it will take about a month before the light comes back on. I'll run it and see if I can find any though. Any other suggestions. I have noticed it sometimes wants to bog down slightly when I hit the gas pedal at a light or stop sign, but then the rpms pick right back up.

That is my first guess. If you are getting too much air to the engine, it will show a lean mixture. Let me know what you find.

Joe

Every time I start my car, the rpm starts going down and then it would jump up and it does that for about 3 minutes and sometimes it will turn off, and then (almost every time) while I am driving, the car starts jerking and without moving my foot off the gas pedal, my speed would go down by itself and then will jump back up by itself after a couple of minutes, and the check engine light flashes during that time (The light is always on usually in my car). Any ideas? BTW I did try and use fuel injector cleaner, because I was told that it could be the problem but did not work. I appreciate any help.

if the check engine light is on, chances are there is a code stored in the computer that will identify where he problem is coming from. Based on your description, it sounds like a bad throttle position sensor, but that is a guess until you have the computer scanned. Most parts stores will scan the computer for free.

Have that done and let me know what you find.

Joe

Engine Performance problem
1999 Ford Explorer V8 Two Wheel Drive Automatic 150k miles

Replaced everything to do with the EDIS module ignition system. still kicking a miss fire code, seafoamed it out. Notta, checked all the vacuum lines on it. Cleaned them out and also looked for leaks. throttle body looks good and no issue. Fuel pressure is at 40psi, which is good. runs good until cel comes on, so closed loop mode.Just has a check engine light that seems to never to want to leave.

Hi To help would you post the code ?

Miss fire code P0300, and sometimes P0306. Going to swap out number 6# injector later today,to see if it's just that.

Check the crankshaft pulse ring behind pully for loosenes or bent. Crankshaft sensor very common in Po300 also common is vacuum leaks and EGR problems.

When i said i replaced the whole EDIS system, i also replaced the crank sensor after it tested bad. ring is good cond still. the 5.0l has really no vaccum lines, all ready checked them. Wouldn't the egr system throw a CEL regarding the evap?

Cam sensor replaced also?

The crank is the cam sensor on this one i believe, compression tested the number 6 cylinder last nite and found nothing out of the ordinary. above 150psi. might try a leak down today, looking for maybe a possible bad valve. Since they seem to always had bad valves since forever.

Leak down good idea there is a camshaft sensor top front engine

Compression tested good, leak down a bit low. Running compression tested good at just a bit more then the 80% for perfect. Higher means exhaust valves. lower means intake. Nice test for FORDS! Did a hard memory restart over the weekend. CEL is now off after 5 miles so far and all sensor at reading at present time.

Great news Fords are very difficult to diagnose and in newer models better but still a pain

I would like to know what wold be causing the o/d light to be turing itself on by itself while driving. does not happen all the time. Also, the check engine light will come on, was told could be due to air getting in by the cap,have replaced the cap, bt still comes on at times but will turn off when cap is taken off and put back on..wait a few days light goes ot, but comes back on after a few days.

First, the light comes on when there is a sensor or other electrical component or emission system problem. Have you had the computer scanned? That is where I would start. The vehicle speed sensor may be bad cauising the OD light to flash, and the check engine light may come on as a result. Have the computer scanned to see what codes are listed. Most parts stores will do it for free.

Let me know what you find.
Joe

my check engine light came on about 3 weeks ago. i took it to advance auto and they put that computer thing on it and the guy told me that older suv's like this one ** the light comes on sometimes when the weather changes or is real cold. and it was cold. unusually cold. well he reset it. well it came on again today so i took it back to make sure it was ok. another guy put the computer on it and said he didn't know what that code was so he asked his boss. the boss said it was probably the thermostat. and he said my antifreeze was low. i told him it was not cause i had gotten it service a couple of weeks ago. well he put it in anyways and it didn't take much of any. ... now that i told u all this. do i need to put a thermostat in or is it the changing (very cold) tempertures we have been having around here. or is it the 02 senser. could u please give me some direction. my truck is not over heating at all and i'm confused. and yes i'm female and i hate thinking people are selling me stuff i dont need. and i dont want my truck to break down.
thank you
pat

Pat please post the actual code...without that we are shootin blanks! It will be PXXXX...

the man at the auto advance store could not remember the code and he said he erased it but he said it meant or said "close fuel control" - temperture koolant low. he put some in but it was such a small amount that would even go in.
thanks
pat

Maybe this one?

Test both ECT(engine coolant temp) and (Intake air temp) sensors with an ohm meter, readings should be as in the chart above, some IAT sensors are built into the MAF(mass air flow) sensor. Most common and cheapest is the ECT about 20.00! ECT is on left front of engine in front of the throttle body.

does this mean i need a thermostat. or is it a sensor.

i'm sorry i realize you are telling me it's something else. but since i don't know much about this i guess i better take it somewhere.

thank you so much

anyways. you are talking about a sensor, right. not the thermostat that i bought right.

i'll leave you alone on this one. i just want to know if i should take that thermostat back and find some one to fix the sensor. also will my truck mess up if it takes me a little while before i can get the sensor fixed.

thank u so much for putting up with me.

i'm done.

Can be either one, but it is most commonly the ECT...you do need to test it as I said Pat...If the thermostat is weak or staying open constantly, it can do this as well...Remove the tstat, boils in water with a thermometer, dont allow the tsat to rest on the bottom, when it opens, take note of the water temp, if it's at the rated temp 195, then it good. If it opens earlier, it's not, or use a hand heal infrared themometer aimed at the thermostat housing, does the engine ever get to 224? The thermostat couldnt have been too much money, if you already have it, install it, and see if the light goes out after it warms up...Book calls for testing the sensors, but temp is temp!

I have a 1999 Ford Explorer Sport with the 4.0 efi engine. Yesterday on the way home, the car studdered and stammered when I hit 50 mph but after I cleared fifty, the car sort of stopped the vibrating and the stammering. This morning when I started the car, it was running really hard and on my way to work, the check engine light came on. I plan on stopping at the autozone and let them hook up the little meter to get some codes. I would look up the codes and hopefully I would get a better idea of what is going on... Please advise... The car has never given me any trouble before...

Let me know the exact code numbers you have and we can go from there.That is our starting point.