This is a continuation again of a previous post but I figured i'd update it. It seems like the car is starting to die in shorter period of time than before. When cold, it'll start up fine and idle for about maybe 7-10 max, then it progressively starts running really ****ty (backfires, stumbles) then finally dies. This is since its been parked in the barn, I had some real horror stories of it doing this to me on the road. I've since got a fuel pressure gauge on it, during idle it sits at about 36-38 psi. It drops slightly when I bump the throttle, but always comes back up. When the engine starts running crappy it seems to almost increase in pressure and the needle vibrates but probably only because the engine is running so erraticly. Nonetheless, the pressure never falls off significatly to rule a bad fuel pump. I've pulled the MAF harness only to have the engine act the same way. I even pulled the oxygen sensor harness apart and it did the same thing. Can a bad opti act this way? It runs smooth up until it falls on its face. Anymore help would be great guys....

 

anything?

 

Since you did a good job of ruling out the fuel pump. I would have to say you have an electrical component in the ignition system or engine management breaking down after it heats up. I think you should try this with the car completely cold. Start if for just a second or 2 to be sure it is running ok. Then get your hair dryer. Heat up one component at a time until it's just too hot to touch. Then try the engine quickly while the part is hot. Keep doing this until you find the problem part but each time you try, don't let the engine run for more than a few seconds. Try not to heat up more than one part at a time. Be sure to do the ICM, the coil and last the PCM. If they don't show the problem, try the opti but that should not be a problem with heat.

Hope that helps
Dave

 

my bet would be bad opti or coil breaking up when it gets hot