Fuel pressure is at 40 psi at idle. Does that sound right?

Yeah theres no cats, but can a clogged muffler cause this?

 

40psi is good.

If it was bad enough I suppose it could.....but I have no idea what could clog it(unless it just flat out fell apart inside...hehe, or someone stuck some potatoes in the exhaust pipe). Do you have any easy way to disconnect the exhaust from the ypipe to try it?

Does your map sensor show a change in readings from closed throttle to wide open? Does it have any trouble starting? How's the fuel filter? New? Old? Any idea?

Have you done any work to the car before this problem started? Or did it just all of a sudden show up?

 

I unhooked the muffler, made no difference.

I dont know about the MAP readings, i'd have to borrow the scanner again.
When i try to start it, the starter clicks about 3-5 times before it actually starts. Sometimes when it starts i have to give it gas, or it either dies or it stumbles and sputters making its way up to 400-500 rpms.

Well my old engine seized. Then i bought the engine it has now from a 94 corvette with 59k. When i first dropped it in, it fired right up. Worked perfectly. Then i turned it off, finished hooking up the rest of the exhaust (only had the manifolds hooked up). When i turned it on again, it started doing this.

Today i was checking the spark plug wires and i noticed that if i unplug #7 cylinder spark plug wire, it makes absolutely no difference...

 

So....could you take the exhaust off all the way back to the manifolds(make it just like when it was running fine)? Are you absolutely sure nothing is clogging it from those points back?

I don't mean to be creating work for you, but in the line of troubleshooting...if something changes when you do something, then it's best to try and take it back to when it was working okay to try and eliminate possible problems.