My engine is misfiring?

Yes it is. It means raw fuel is being dumped into the exhaust and burning down stream. You need to get this fixed before it fouls the converter. Most likely your coil pack is faulty. Here are two guides to help us fix the problem.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

and

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Please run down these guides and report back.

I have replaced coil pack, plugs, I.C.M, and injector seals.
could it be fuel pump regulator or fuel pump?

No. You are getting fuel in the cylinders, but it's not firing. You can however test the pump pressure to be sure, but then pull the plugs one at a time and see if they are being fouled by fuel. If they are, look for a leaking pressure regulator, as sometime it will introduce too much fuel into the intake and foul the plugs.

Next look for leaking injectors. This has nothing to do with the seals around the outside of the injectors. This will be an internal leak that allows fuel to go into the cylinders at the wrong time, which will then go out the exhaust valve unburned.

Its random but there are usually 2 'sooty' plugs and 2 'wet' plugs. Random asto in what order.
Injectors checked o.k. while out, compression is o.k. also.
Fuel pressure regulator is discolored.
The fuel pump can be heard but I did try without fuse and it made no difference to engine performance?

the fuel rail is also discolored around the base of the regulator!

That would be an external leak. That may also be a problem, but keep in mind, there are two kinds of misfires, ignition and lean. An excessively lean condition will cause your exhaust to overheat and glow red, but it's not as common a condition as unburned fuel entering the exhaust and being burned inside the tail pipes or causing your cats to light off.

I'm not always 100% correct, as no one is perfect. But I believe your misfire is causing this second kind of condition. Unfortunately it's not always easy to hunt down. You just have to go one step at a time until you find the problem. But remember to test, not just replace parts. Only replace when you know that part is faulty.

I have replaced 2 coils, coil pack housing, I.C.M., plugs and boots what else could cause a misfire?
What should fuel pressure regulator pressure be if a gauge was used?

First pull the vacuum line to the regulator and check for the presence of fuel. If there's any, replace it.

Fuel pressure should be 41-47 psi.

There are MANY things that can cause a misfire, including but not limited to:

Bad computer, failing sensors, you forgot to put the dielectric grease around the insulators of the plugs when you replaced them, there's a bad ground to the coils, the coils wires, connectors are bad, the injectors are clogged/leaking, etc.

The thing to do is eliminate one thing at a time, beginning with the ignition system, then fuel, then sensors, then computer.

It was the fuel injectors cause the issue this guide helped me find it.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Thank you for the help, it is much appreciated.

What could cause my car to start missing. It starts and idols but has a bad miss, no power. It has not made the check engine light come on. The plugs are firing, compression is ok, What could be the problem?

Engine running rough or misfiring can be cause by the following:

1.Defective spark plugs
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression

Goover this guide to help find out which one

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

i have a 95 cavalier just had the head gasket redone and everything was good till about 1 day later and all the sudden my car was idleing real rough bouncing between 600 and 800 rpm and i replaced the plugs had the sensors checked it all came up good and we ran the diagnostic tester on it and i had no check engine light on but it came up as random misfire but would not say where my mechanic thought it was vacuum lines but that was good too im just wondering what is going on with this junker, i also have what appears to be fuel in my intake because i take the whole air cleaner assembly off and at he bottom there is liquid and it is not oil and i replace the fuel filter to and fuel injector o rings

Random misfie...head gasket just done...I think I would have the compression tested in the cylinders. Perhaps the head is cracked or gasket instalation problem, gasket defect etc.

what would make the gasket not install properly just wondering?

Now the motor is starting to tick a little bit sounds like a lifter should i replace the head gasket and all the other gaskets again?

Incorrect tightening sequence or incorrect torquing.

I understan dyou unplugged a sensor but need identification? Can you give the location and or a pic? how many wires go to it?

On the expressway (& car warmed up), when aproaching the speed of 45-55 mph the car starts to shudder (shake) and is fine once i get it past there. Then once the cars been run and i am coming off the expressway down the ramp and am almost to a stop the car jerks hard like its gonna stall and sometimes does. What could the problem be?

is there a chec engine light on?

No, there is no check engine light on.

when was the last time you had a tune up

Just had a tune up 2 months ago

i would suggest having someone with a scan tool look at your computer system and see if anything is staying egauged like a torque converter solenoid, maybe an engine sensor reading incorrectly, fuel pressure maybe low.

1993 cavalier , 4 dor , 2.2L 4 cylinder , auto trans. 125,000 miles.
This car went from running fine when it was shut off , to running on 2 cylinders 20 min. later when started up again. The 2 plugs on the outside are not firing. the 2 inside ones are. I have replaced both coils , & installed a new computer with no change.

Is there anything else I can look at.

THANKS !!!!!

I think you can switch the coil packs and see if the same two still don't fire...
If all coils are good and two are not firing..if it is not terribly bad plugs and wires...it just might be an ignition module.
You tend to lose spark on two at a time with coils and modules..on GM's

Like rhall77 suggested the TCC is not unlocking. You can try disconnecting the TCC electrical connection. This is ususlly a square 4 prong connector connected to the trans.
If this stops the problem, then the TCC solenoid would need to be replaced and this can be done without removing the trans from the car.

Thanks for the tip. I will try the scan and see if the torque converter solenoid is the problem. If not i will reply/ repost. I appreciate the your time.

Engine Mechanical problem
1993 Chevy Cavalier 6 cyl Front Wheel Drive Automatic

Engine is missing at varing speeds and sometimes at a stop when in drive and out of gear.

Do you have the 3.1L V6? WHen was the last tune up? Has the check engine light come on? Have you checked for vacuum leaks?

Hi I found 2 broken wires when trouble first started.
replaced wires and plugs drove it for 6 days,then it dies again and would not start.I had no spark found out control module was bad replaced it.discovered the new wires were not good replaced them again.drove it to work and it drove fine.on the way home from work if i got up to about 35 mph it would stall but restart right away.also sounded like a misfire.
when i got home i went to check plugs to make sure nothing was wrong from other trouble they needed to be gaped. and also got another bad set of wires,so returned they other and got yet another new pair. now it will start for only a few seconds and stall,some times make a popping sound.I double and triple checked firing order. also the ignition coils were tested and they claimed they were good..
could someone please help.I have been laid off for sometime and finally got a new job,and now I can not get to my new job.I dont have much money at all to get this car fixed right now,So I need to try to figure out the problem myself and hopefully fix it.
Please any suggestions would be greatly appreciated.
thank you so much for your time.

i know you checked the firing order but check it one more time. also check the crank position sensor, make sure its not broken. and double check the wiring to the Ingnition module

Shakes or Wobbles problem
1992 Chevy Cavalier 4 cyl Front Wheel Drive Manual 270k miles

Ok, i recently installed a new airtex fuel pump from Autozone, hooked up, rewired the harness because the old harness was different from the new one on the fuel pump assembly. I used two out of three butt connectors to put the wires together and taped the last ones together with electrical tape. While I was driving back down this backroad last night after getting 6 bucks in gas at this gas station. Car drove fine until I started getting on these back bumpy country roads. While driving after 20 mins, the car starts jerking violently, hard. It felt as if the engine was trying to jump out of the car. Symptoms that my car currently has is a catalytic converter that is a little clogged up, but not much. Also I have a fuel injector that is leaking badly. While driving last night, the bucking would clear some, when i came to a sign, the car shut itself off, and flooded. So I pressed the clutch in, cranked it, nothing. Held the gas at WOT, cranked it and finally got it to spudder after smoking a little ( cold outside ) it cranked up and i stomped on it and got towards town. Driving a little further, it stops jerking, then starts back right when I get into town. I park it, haven't touched it this morning since Ive got it back to a safe place for it to sit. My question is, could it be a wiring problem when i hooked up the fuel pump, disconnecting the wire maybe throughout driving range, the leaky fuel injector, converter, or some type of mas or map sensor problem? I dont have much money at all this week til friday and need help clearing up what it could be. Thanks alot!

double check your wiring and make sure that is is secure. also, do you have a check engine light on when it happend?

No check engine light at all. :(

I'm gonna check the fuel injector tomorrow, hopefully just a busted oring.

Please help, I have developed a miss in the engine, changed plugs, wires, coil packs, fixed the problem, but it started again, can these things have already gone bad or is there something I've missed. Sometimes the miss gets really bad and the car acts like it will stall, give it gas and in a few seconds it will run again.

is there a check engine light on?

there are a couple of other things that need checking. dirty airfilter, egr valve, intake manifold, also check the accordian hose that leads from the airfilter box to the throttle body

https://www.2carpros.com/how_to/how_to_tune_up.htm

https://www.2carpros.com/how_to/change_air_filter.htm

https://www.2carpros.com/kpages/first_things.htm

car will run fine and start sputtering again as if running on 3cyls again. tried to check all vacuum line as many as i could fine. they are ok, my only guess might be coil packs but az said possible control module. car has sat for 5 months and a wonder it cranked. once it runs fine rpms saty constant at 2000 rpm's then slowly idles down and starts the sputtering again? suggestions please.

[quote:818055042d="legitimate007"]is there a check engine light on?[/quote:818055042d]


found the map sensor it was unplugged for manifold, but still have a small miss. the check engine light was on, and i got the code, it was the map sensor. now the light is off and no more codes, but still can't seem to fix the miss.