1988 5.7 w/TBI

[szwedj]

This is in a 3500 truck. Motor seems to run ok up to about half throttle, then it flattens right out. Where would you start to look? Changed the fuel filter so far. No error codes yet but I'm not sure I have run it enough to trip a code yet. The truck has set most of the winter with a dead battery. I was told it ran good when parked. My fisrt thought was it wasn't getting enough air but it has a new filter. Both injectors seem to be working, atleast I can see the fuel spraying from both.

Could it be and injector or the TPS? Any help would be greatly appreciated.

 

Thanks,

Joe

[szwedj]

Turns out to be the cat. At first I didn't think it was the cat, but then I took it for another spin and it just seemed plugged up. So I brought back in the shop and dropped the system right at the Y pipe. Took it for another spin and it runs fine. I didn't realize that a plugged cat would make it shift so hard either, but it shifts real smooth now to my suprise.