Ok so heres the long story, I bought the car not even a year ago and when I was driving it home the CEL came on and it was a oxygen sensor I replaced both of them. Shortly after this the car started the stuttering problem. When you first start it and its cold it starts fine no problem, as its warming up it will start to spit and sputter and sometimes die. If you just rev the motor to like 4k rpms it runs fine and doesnt do it. But when u get to the first stop light it will die. after this or when the cars warmed up it doesnt do it. If you turn the car off and let it sit for like 20 minutes and start it, it will do it. I replaced the fuel filter, spark plugs, coil packs, and fuel pressure regulator. So i just dealt with it for a while and then the motor spun a bearing. I replaced the motor a few months ago witha gm crate motor and the problem is still there. I switched to a heated o2 sensor for the exhaust manifold and that seemed to make things a little better. I finally replaced the IAC valve, and reset the computer this made the problem much worse and caused the computer to finally kick a CEL and it was a random misfire. I replaced the coil pack housing and throttle positioning sensor, the throttle positioning sensor they gave me is bad and so i put mine back on. The new coil pack housing got rid of the miss and it runs good except it still bogs and dies as it always has. All the vacuum lines appear to be good. I am at a loss and have no clue in wich direction to go in now. When its stuttering and you give it a little gas it makes it worse, if you punch it, it seems to be ok. When you let it idle and it does it sometimes u can see black smoke out the exhaust. I have replaced some other stuff but it was for the new motor going in not due to the stuttering. Any help would be appreciated. I may go out and record a video of what it does just cause its hard to explain

Recap

things replaced

o2 sensors (got rid of cel)
spark plugs (did nothing)
fuel filter (did nothing)
fuel pressure regulator (did nothing)
coil packs (did nothing)
GM crate motor
plug boots
switched manifold o2 to a heated o2 sensor (helped a little with idle and starting)
iac (made problem worse and produced a random misfire code)
coil pack housing (got rid of misfire and runs alot better)
TPS (they gave me a bad one need to exchange for a good one didnt even test old one)

Thanks

OK so it is definately a misfire. I pulled the spark plugs and the center 2 plugs are alot darker then the rest. It does it the worst when its trying to go to its normal idle. It trys to go to its normal idle and thats when it misses. The Map pressure is reading 12.4, and is idling 1068 when it kicks the CEL, the temperature is at 168. I'm thinking maybe injectors but otherwise im clueless.

My car did the identical

I put in new plugs, seafoamed the tank and the intake vaccum hose, and new plug wires.

Problem solved.


99 cav 2.2L 212,000 miles
97 cav 2.2L 110,000 miles
91 cav 2.2L 236,000 miles RIP
04 Silverado Z71 Ext.Cab 55,000 miles
01 Suzuki SV650 22,000 miles
97 Arctic Cat ZRT 600 6,000 miles

ok so I took off the intake to check some stuff out and you can see that the outer 2 cylinders are almost wet, and the inside ones are dry. So I guess I am wondering if anyone can tell if this is a spark issue, or fuel issue, and on wich cylinders?

pic of intake side of the head



pic of spark plugs in order




Matt, thanks for the reply but I have already replaced the spark plugs and seafoamed/ cleaned everything from the intake to the egr valve.

At first i was thinking it could be your cat, but i do not believe a bad cat would cause excess carbon build-up on the plugs. I would get a good scanner and look that the injectors while the engine is running. Im thinking they are dumping in too much fuel. It could be then injectors themselves or somehow the tune got messed up or a sensor isnt working properly.

Things I'd check
Test for Spark (are 1 and 4 even firing?)
Pressure from the tank after the sending unit by pinching the return and make sure it holds pressure, if it doesn't your sending unit is bad. Does the 2200 have a cam sensor?


-Chris

IamRascal wrote:Things I'd check
Test for Spark (are 1 and 4 even firing?)
Pressure from the tank after the sending unit by pinching the return and make sure it holds pressure, if it doesn't your sending unit is bad. Does the 2200 have a cam sensor?

Yes, 1 and 4 are firing, not sure if its all the time or not but they do. As the car warms up the miss is only there at idle. I have the fuel lines off, is there a way to test the fuel pressure a little more accurately? Oh, and it's a 2.4l.

I have the injectors soaking in some sea foam so hopefully that will help. The other thing that may have been the issue, I found a flake of metal about 3/4 of an inch long, by about 1/4 of an inch wide in the fuel rail pretty much covering an injector. May have had nothing to do with it, I dont see why it would miss on 2 cylinders tho? I guess I will just have to try and find out.

Thanks,
J Rigby

I think that piece of metal would definitely have something to do with it. Maybe not your entire problem, but thats A LOT of blockage for the amount of fuel your injector actually try's to shoot. If the engine is running its probably not a pressure problem. I would at least try replacing the fuel filter to see if that helps.

I was thinking eco when I referred to the fuel pressure. We have a test port on the feed line so its easy to check.


-Chris