i have a 4g63t in my talon, and when i go to start it up it fires up just fine and idles normal, but after a minute or so it runs like crap and wont accelerate past like 2000rpms at the most. What could be the problem with this? were thinking either the wrong ecm was put in before i got it or the fuel pressure regulator is bad. Also when we turn the crankshaft position sensor while its turned on, it will run decent for a little, but then would run like crap. i ran a scanner and the only thing showing up is the front o2 sensor which was unplugged when we did the scan, but was plugged in when it was running bad. i also did a boost test and found no leaks as well as checked the timing and it was fine too. we did a fuel test too and it is fine. any suggestions would be awesome thanks

 

bump for any suggestions

 

What year is the talon? Try swaping out the maf w/ a known good one.

 

1995. thanks for the suggestion, seems to be coming up a lot