what the hell is going on here? this is my 3rd cls-6 and I have never had this problem before,I have owned comptech and XS headers and never had this problem. car does not accelerate as it should! any ideas? not throwing any codes and exhaust is leak free!

 

Reset the ECU and try again. Does it feel weak in general or just some parts of the powerband? Try seafoaming the car to see if there are any leaks visually, helps me.
O2 sensors all plugged and screwed in properly? Put back all the vacuum lines? The left vacuum line on the IM fittings if disconnected will leave you without CC but who knows what else can be left hanging.

Do you have time tomorrow for me to check out the car?

 

give it some time for the ecu to adjust? my car felt shitty slow the first time i slapped my headers on. give it a little while and see how it turns out.

 

Weird, I never had this problem just as Mike said for himself earlier, seems like you would feel something at least maybe not the max potential at first but I don't see how it would run shitty rght after install.

 

Maybe they're leaking?

 

hope u figure it out

 

quick ecu reset - unhook bat, let sit a few, then hook it back up and start her up with no aux. electronics on. Don't touch the throttle for 10 mins just let her idle. Hopefully that solves your problem. Does sound strange.

 

oh man, checked everything.. nothing is loose, just seafoamed the bit** inside and out,(vaccum-tank-eng) still running weak? the headers are brand new and I had them installed at acura of cerritos? I need to go pick up my old ones today(yes they kept them even though I specifically asked for the old ones to be put in the trunk).. im gonna go use different gas and octane booster,maybe bad gas?imrc?

 

different gas??? were you not using 92/93 octane already

 

drive it around and put like 50 miles on it. most likely the characteristics of your power will change. if it does not change after a while of driving, you will know for sure something isnt right. even if it doesnt change than you probably will at least get a better idea of whats wrong after driving that much. go cruise around and kill like a 3rd of a tank and let us know

 

main O2 sensor is possible culprit, damage may have happened during header install.
check sensor wiring for ground fault, however it should show code if malfunctioning.

 

get it tuned! h/i/e/pipes gives you hp but not torque... well, maybe a bit...

 

Mike just let me know if yu want we can check it out. Should be relatively easy to figure out to someone from an outside perspective.

 

I'd inspect the main o2 sensor.