This has me a bit stumped. My car is running great except right at WOT. It doesn't seem to matter what RPM the engine is at or what gear the trans is in, but as soon as you reach WOT it instantly falls off and starts sputtering. I have not replaced the TPS, but I have reset it to .54 and it has a smooth voltage increase all the way to WOT and will stay steady while you hold it open. When you reach the point where this sputtering starts you can slightly back off the pedal and it will immediately come back, if its in 1st gear it will break traction when it comes back. Any ideas what this might be before I just start throwing parts at it?

 

Anybody? This is an 85 TA LB9. This thing runs smooth as silk until right at wot. The cat has been removed.

 

Have you checked your fuel pressure?

 

The answer is no. I have just replaced the FP with a walbro 255, new filter, and a new diaphragm in the regulator. It was doing this before I changed these parts, but everything else seems to be acting normal now except this cutting out.