Have you tried to move the coil to see if the misfire moves with it? Also, how did you check the sensors?

Can you post the exact codes the PCM is throwing?

 

working on this car tonight - put in a different coil from another engine and misfire reading continues on cylinder #1; code was PO302 or something like that. Code does not come on all the time. Sometimes no code - no check engine. Would gladly talk with you as I really need help. Checking the injectors - not sure what I'm checking for. Can they be cleaned - I have another engine that has bad heads for backup. I added Seafoam and it cleared it up and the car ran great for about 100miles and then more problems. Lifters and valves sound ok. Had fuel injector sensor out and car ran the same with strong gas smell -did that just now. Guess I need direct guidance. Help!

 

working on this car tonight - put in a different coil from another engine and misfire reading continues on cylinder #1; code was PO302 or something like that. Code does not come on all the time. Sometimes no code - no check engine. Would gladly talk with you as I really need help. Checking the injectors - not sure what I'm checking for. Can they be cleaned - I have another engine that has bad heads for backup. I added Seafoam and it cleared it up and the car ran great for about 100miles and then more problems. Lifters and valves sound ok. Had fuel injector sensor out and car ran the same with strong gas smell -did that just now. Guess I need direct guidance. Help!

So that rules out the coil, have you tried replacing the plug and wire yet? Is there any way to get me the exact code?

 

Went to Advance for the code reading - can't remember the exact code. Checked out some of the sensors with Ohm meter- seem ok. No check engine light on now. Could the Sea Foam messed up something? Fuel filter? My mother tells me sounds like the old carburator problem - she's old school, though! How would that translate to injectors - air/fuel mix? Thanks

 

A PO302 is a cylinder misfire on cylinder 2.

Without the exact code, I am afraid I can be of only limited help.

 

How about PO301?

 

How can we be sure which cylinder is misfiring if we don't know the exact code?

Here is what I suggest, replace the plug and wire on the cylinder that is misfiring, reset the code and see if it comes back.

 

I already tried that -- I bought new wires and put one on the #1 and then I gapped the plug etc and replaced it. Are you saying I need to buy a new plug - these are Autolite I have - less than 1000 miles on them? The check engine light does not come on all the time - it's not on now! I 'mthinking of replacing the #1injector - what is your opinion of that?

 

I already tried that -- I bought new wires and put one on the #1 and then I gapped the plug etc and replaced it. Are you saying I need to buy a new plug - these are Autolite I have - less than 1000 miles on them? The check engine light does not come on all the time - it's not on now! I 'mthinking of replacing the #1injector - what is your opinion of that?

It could be a the spark plug has been cracked when you installed it. Many times you cannot even see the crack. This would cause a misfire. Or perhaps a wire has been burnt or cut. You can continue to spend money replacing expensive components, but it's cheap to replace the plug and to move the wire to another cylinder to see if the misfire follows the wire. Why not swap the injector to another cylinder and see if the misfire follows the injector?

 

what is the brand of spark plugs that you bought? i had this same problem, it was the plugs, they were supposed to be high performance and amazing, they ended up making my cars engine idle bad, run bad, drive bad, and loss of power, and misfire, they were e3. they also made many other things in my car go bad.

EDIT: dont depend on it being that though, it also could be that your running rich, some common symptoms for that is sluggish power, loss in mpg's, black residue on tailpipe. it could be something else though, im just fishing around for ya, sometime bad oxygen sensors dont throw a bad reading thru the computer, i would get the accurate code tho, as Bob said.

 

Get a new plug and wire. Just because it has 100 miles on it, doesnt mean the plug couldn't have fouled or the wire is shot.

For cleaning injectors, just go to autzone or something and buy some injector cleaner.

 

Get a new plug and wire. Just because it has 100 miles on it, doesnt mean the plug couldn't have fouled or the wire is shot.

this is true.

 

Also check your fuel pressure regulator. Pull the vacuum line off of it, car not running, there should not be any fuel on the vacuum side. If there is, replace it...Not fun but I did it.
Scott

 

Hello forum - need help again - 3800 - hesitation/ rough idle; stumbles on acceleration - smoother at rpm's below 2500/ burning rich - increased fuel consumption. Feels like it's going to stall out. Checked compression 125 on 2 cylinders #1 and #4. Checked sensors - seem ok; checked coil/ ignition module - seems ok; what else? New plugs/ new wires- less than 500 miles. Plugs look good. Started acting up once in a while but became worse over a week's time.

I noticed the fuel filter was not addressed here. I ran into a simular prob on a different car and it was a very clogged fuel filter.
Let us know if you fixed it and what is was.