Alright this is what goin on with my car.

It sputters and has decent power until about 4k rpm. Above 5k rpm it starts to sputter and backfire bad. It doesnt idle well at all. It idles at 500 and wants to die, then it climbs up to 900 where it is set at.

I also am getting a map sensor reading of about .65-.7 at idle. When i cruise in 6th gear and give it some throttle, the fuel pressure starts to jump between 41-45 psi. The fuel pressure doesnt drop when at full throttle.

I thought it might be ring because my when i last changed the plugs all were white except for one which was black. BUT... i noticed right after i put those old plugs on that i didnt connect one of the plug wires for about 20 mins of hardcore driving. Would that cause a plug to foul out and turn black and stay black for a couple weeks?

Now im leaning towards a blown intake gasket.

Gaskets, or rings? Any ideas?

 

oh yea, i reset the BLMS and set the computer to go into closed loop at 300*, so it isnt an o2 problem.

 

It's not a bad intake gasket. That would only cause you to be lean not rich. If you have a black plug, it is either hard and crumbly from burning oil (doubt it) or kind of velvety looking from being rich(probably). Running rich could be several things. Bad spark as in bad plug or wire or bad track in the distributor cap. Low on compression from a bad valve (doubtful). Low compression from bad head gasket(doubtful). Sticky injector pumping too much fuel into that cylinder (good possibility). Bad fuel pressure regulator diaphragm leaking fuel into the vacuum line and into the intake but this effects cylinders on the passenger side more and your pressure readings don't seem bad so I doubt that is the problem.

You should look to see if that cylinder is dead either from spark or injector. You should keep an eye or should I see nose on your oil. Many times a bad cylinder will dilute the oil with fuel. This is bad for 2 reasons, one is obvious at the rods and the crank. The other is the cylinder in question is washing the oil off the cylinder walls and could gouge it.

Also you can see if you are leaking fuel into that cylinder by monitoring fuel pressure after the engine is shut down to see how fast it falls. You should also do a leak down test on the bad cylinder.

 

The black plug was on the one that i didnt connect. I dont think it is a problem with one cylinder.

It runs strong until 4k rpm. It isnt ignition, i have delteq. And it there is a funny sound comming from the engine when its pulling vacuum.

 

Resest your pcm to stock. If you still have the problem Im about 99% sure it is your opti.

 

Im not running an opti, its on coilpacks. And why would i set the PCM to stock with a cc306 cam and ported heads? It was running fine before **** started going down.

OK, the black plug was most likely caused by a disconnected plug wire, so keep that in mind.