Don't hit me, I searched

Been trying to figure out the problem. I have a bad idle and a "studdering" exhaust after the car is warm. On top of that, I can't get more than 200 miles to a tank of gas, no "power", and I think I am running rich (I know...bolt ons). Mods: AEM CAI, Greddy Evo catback and Greddy headers. Pulled codes P0300 and P0303. Misfire in cylinder 3 and random misfire.
Here is what I have replaced:
- Cap, rotor, coil, fuel filter, and pcv valve (All OEM parts)
- Wires (NGK) and plugs (NGK BKR6E-11 gapped @ 1.3mm)

Here is what I have tested:
- ICM input - PASSED
- Resistance for TDC/CKP/CYP sensor on distributor (got 0.38 ohms)
- Idle set @ 750 RPM
- Compression @ 220 in all 4
- All old plugs had quite a bit of carbon on them
- Valve/cam timing and tension is perfect
- Base ignition timing set @ 16 deg (RED)
- Swapped injector #3 w/ #1
- Computer has probably been reset 20 times
- No air in cooling system
- MAP sensor @ 33 when @ idle
- Valve adjustment

I noticed that if the engine is warm, and I swap my new plugs with the old, that the engine seemed to idle great-until the plug got hot. Tested for spark for all cylinders. All seem okay. Tested injectors. All spray nice and don't leak. I did notice a couple of things:
- The rotor inside the distributor seems "loose". If you grab it and try to move it around-left-to-right, it had a small amount of movement.
- When the engine starts to run like a dog (when warm and sputtering), if I remove the spark plug wire from #3, it sounds the same. Swapped plug-same result. Swapped wires-same result.
- As the idle RPM increase and decrease, so does my ignition timing. It is CONSTANTLY getting retarded or advanced anywhere from 12 degrees to 18 degrees.
- Pulled out new plugs. All look good except for #3. It is "carbonized", probably fouled.

I'm now stuck. Not too sure what to do. I'm thinking distributor because of the resistance test on the sensors, but how much of a failure tolerance do our distributors have anyways? The resistance is supposed to be in between 0.5k and 1.0k ohms, and I am at 0.38k ohms. Don't think that it is an issue with lack of fuel pressure, but if anyone knows where I can find a freakin banjo bolt adapter, please let me know. What about too much fuel? Is there anyway to test the pressure regulator w/o a fuel pressure tester?

Any help is appreciated. I'm not really looking for the "magical cure", just a couple of fresh ideas for me to look at. Thanks!!

 

I would say the basic new spark plugs, wires, and distributor and it should fix the problem

 

Since you haven't done so, I'd replace the fuel filter as well...just so you can rule it out. But, it sounds to me that you are having a spark problem in the #3 cylinder. If it was getting spark, when you pulled the plug wire from #3 cylinder, the engine would not sound the same. However, the fact that you have replaced the cap/rotor/coil and still have the same problem in the same cylinder is very interesting. And since you swapped the injector as well and still have the same problem rules that out.

As for the fuel pressure idea, if that was the problem, it would be the same in all cylinders...so it's definitely a spark problem. If you wanted to test fuel pressure, you'd need a gauge. I know B&M sells a filter top gauge that comes with the correct banjo bolt for it.

I'd try swapping out the distributor if you know someone with the same OBD version GSR as you. At least you would be able to rule out the distributor even if it was still giving you the same problem.

I guess it could be an ECU problem as well...so if swapping distributors doesn't help, try running another GSR ECU. Maybe something funky is going on there...shit happens sometimes.

Good luck, and keep us updated.

 

As dubcac suggested, try swapping the distributor with a known working distributor and let us know.

BTW, good job on troubleshooting it. Sounds like you've done most all that you can.

 

Thanks for the help fellas. BTW, I have already done all minor maintenance items i.e. fuel filter, plugs, wires, cap, rotor, etc. I think I'm going to snatch a distributor from a junk yard. It just doesn't make any sense. When it idles like crap, I really can pull out the #3 plug wire, and it doesn't make the same difference in engine sound as if I pulled a plug wire from another cylinder. Even with my datalogger, it doesn't change rpm or time as much.

 

Datalogger?