Just put my stock exhaust back on and now my car is stumbling at high rpm in vtec.

I had an HKS single with a test pipe on for track. Only other mod is K&N fipk.

doesn’t seem like a mis fire, I’m not getting any codes. It’s not as hard as fuel cut either.

car is an ‘01 w/130k

i read somewhere about cleaning MAS but my car has a MAP sensor and it doesn’t look dirty.

 

Did you put back stock cat as well?
It's not uncommon for it to fail and block exhaust flow.

 

yes, cat went back on.

could the computer be recalculating the fuel map?

ran a little better last night

if it keeps up I’ll try putting the test pipe back on to see what happens.

 

Is the cat broken or clogged?

Does the engine have enough oil in it?

No, this is not a computer calibration issue. The car shouldn't stumble when switching exhausts.

 

Did you tighten the exhaust flange bolts properly?

 

Check oil pressure? Check solenoid screen? Oil consumption?

 

Thanks for all the feedback checked everything flange bolts are tight. Oil is good, problem seems to have resolved itself.