95 lesabre random traveling misfire

[papa smurf 5039]

so i bought this knowing it probably needed a lim gasket at the very least. this was about 2 years ago. over that time i found the coolant elbow had broken off inside LIM. so i replaced that and the lower and upper gasket for good measure. after putting all back together alternator wouldnt charge. ended up being bad alternator and bad exciter wire circuit/driver within pcm. the pcm wouldnt send any voltage to alternator. so ended up wiring alternator to voltage with on/off switch to make functional. at that time i didnt know if pcm was bad or just wiring from pcm to alternator. so then i had stalling. so i replaced crank and IAC. ran better still stalled and TPS was new when i bought vehicle so figured it was good. (also checked with actron scanner). still had stalling. the radiator fans started acting up and eventually only low speed would come on. so replaced PCM now i havent had a single stall. with my new actron scanner i can finally have some info from OBD1.5. i have a option to monitor cylinder 1-6 with a misfire yes/no chart. i get random misifres on every cylinder. more so when hot. so i replaced all coil packs, wire, and plugs. still get misfire but runs better. old upper manifold was kinda warped so i opted to replace that. had degradation around egr. was looking for vacuum leak. so car has new plenum and all gaskets associated to eliminate any vaccuum leak there. ive tried propane torch and carb cleaner around all vacuum sources and also replaced all dry rotted rubber lines. i havent replaced the ICM and its probably oem. so i guess im looking to see if anyone has any advice? i have good compression on all cylinders and no oil/coolant contamination. all motor mounts were replaced which also took a lot of vibration out. when i go to accelerate it sort of stumbles. feels like misifire and i think its lean. my next step is EGR or ICM. I also have 32 pounds of fuel pressure no droppage. Any advice would be greatly appreciated. (also changed crank sensor)

 

[ryenie]

My first suspect would be the ICM, it's seems to be the module most affected by heat. If i'm not mistaken it can be tested at a handful of auto parts stores.

 

[papa smurf 5039]

So while I was helping change someone else's fuel pump I checked my pressure at the scraeder valve. I was getting 32 psi running. I just know looked up what is acceptable for my car. Somewhere between 40-50? I have pulled vacuum hose off regulator with engine off on multiple occasions and haven't had any signs of gas. Would this indicate fuel pump? The regulator is all most twice as expensive as pump and I'm not afraid to do further testing and change fuel pump or regulator if necessary

 

[papa smurf 5039]

Just changed ICM. still misfires. I didn't replace one coil pack because it was new when I bought it. I cleaned egr and now I'm lost really

 

[HotZ28]

You do have low fuel pressure, which is on the borderline of what is acceptable! This problem is hard to troubleshoot from here, but if you Click Here it may give you some ideas on other things to check for an P0300 code.

 

[papa smurf 5039]

My manual says 32 psi is normal. When I pull the vacuum line off it jumps to 40 psi with no change in performance. What is the correct fuel pressure? Fuel pump is only $60 so not a big deal for me really