my talon AWDwont go any faster than 30mph. It accellerates normally until it hits about 25mph then it just stops and SLOWLY climbs to 30mph. The car had a lot of problems before, the timing was off so I put a new belt in and got the timing right. Then there were more problems and I took the ECU out of a 97 GSX and it solved the rest. The car runs perfect while idling and while idiling it will hit redline with no problem. The car also runs very very rich and it doesnt change whether I raise or lower the fuel pressure.
What might be causing the car to do this?

 

cat converter

 

Sounds like an intake air problem to me. Either you have an intake leak or a blocked passage. I would check everything leading up to the intake plenum, then check to make sure all of your vacuum lines are good.

 

I checked my intake and my intercooler piping and they werent leaking or blocked. I also checked my vaccum lines and they werent leaking. I do hear a slight air leak if I put my ear right behind the intake manifold and I cant pinpoint it but it doesntsound like it is big enough to cause this problem
and i have no cat conv

 

I wanted to see if the car would even go faster than 30mph so todayI put the car up on jackstands, took the wheels off of the car,cranked it up and the car accellerated normally and I 'drove' it through the gearsthe speedometer even started readin 150mph
So wouldthe problemstill be aboost leak ormight it be a fuel problem that happens when the car is under a load?