[QUOTE=Tom_Sawyer_Man;1436289]Did performance worsen after FPR and fuel rail were changed?

It seems it was the same since they switched the fuel rail. This was only an at idle problem when engine is hot. Then it slowly changed to an all around drive-ability problem. After the FPR change didn't change anything. The odor of gas I describe is coming from past the air filter on the throttle body side. I have another MAF so I'll drop that in tomorrow and see if that helps.

I officially give up. Off to a diagnostic shop!

As I had mentioned before I took out all plugs and they all looked the same with a white ashy appearance. I even checked the gaps and regapped about half that were off a bit. I checked all wires and they look ok with no tears or faults (Only a year old and only 8K). Took off coils tested and replaced, actually got a new one as I had a slight crack in it, so all coils are less than 3 years old. Cleaned all battery cables and ground under ICM. Used dielectric grease on wires, coils and ICM connector. Got another MAF from junk yard. Checked for any vacuum leaks and sprayed around upper and lower intake to check for leaks and found none. Replaced FPR. Swapped PCM for a known good one.

Still same problem. At start up car runs smoothly but after about 2 minutes you can tell it is missing. When fully hot car is "bogged" down and has reduced power. Exhaust has that rotten egg smell (Cat is 2 years old). Oddly no codes after a 10 minute test ride after it warmed up. I parked it and revved engine to 1500 out of gear and got code for random misfire. Also LT and ST Fuel trims are real high, higher than before.

I'll update when I have it properly diagnosed unless someone has any other ideas.

I believe problem lies with the fuel rail switch. It just hit me that they probably used the same fuel injections from the 96-99 car they took the rail out of. A check on Rock Auto and the fuel rail and injectors are unique to 95 only. This would explain why PCM is dumping fuel but cannot supply enough and car is running real lean. I hope the shop still has our old rail and injectors. Parts are so hard to come by anymore. They did the swap to fix a leak at the front connector at the rail. They should have replaced the fuel line and not the rail. They didn't charge me for this but they have created a monster set of problems!!!

It seems that the rail/injectors are interchangeable. I tested the injectors, took off rail and started engine and had gas fall in small cups,all are fine. At idle you can hear at the exhaust pipe the misfire. I believe my last thing I haven't really tested, other than visible, are the wires. My scanner would show cylinder 6 misfire so I had my old wires and swapped and samething. Now the last set of wires a year ago went bad and they were only 2 years old. These wires are exactly a year old. The sound of the misfire is that of a wire misfire like I had last year. I may go ahead and throw more $$$ at it and replace the wires again. I am getting Code P0300, random misfire, so I'm not sure if it is a wire(s) but very well could be.

Well it is finally fixed. My first suspicion of what was wrong was the last thing I did. I changed the spark plug wires. This is the second new set in 3 years. Previous set was AC Delco premium. Somehow this car eats them!