Invidia 70mm test pipe on stock ap1.
 

So I have a bone stock 01 ap1 and just installed a 70mm invidia test pipe and now everytime I shift and get back on the gas it feels like it hesitates, what could be the problem? Im running rich as shit too. Could it be that the test pipe is too big, and I should have gotten the 60mm?

Any imput would be great!

Thanks.

Did you reset the ECU?

How do you know its running rich? It should actually lean out with a test pipe. Do you have an o2 sim. installed? And yes, you should have gone with the 60mm unless you plan on upgrading from the factory exhaust.

01 ecu's run rich too. The pipe will lean it out too.

I don't think the pipe diameter has got anything to do wit it. Check for leaks i guess.

It was a mistake to put a 70 mm on with a stock exhaust. If you aren't planning to get a 70 mm exhuast, then get a 60 mm TP.