I own a 2003 Cobra with several modifications to it. Just recently I reinstalled my factory cats. The car seem to run fine untill I put a ZO6 to shame. I down shifted to 3rd on the interstate and i was at about 70 mph before we took of from a rolling start. When I shifted to 4th the car took a nose dive before boosting up again, it was if the tires broke lose and the traction control came on but i had no warning lights. I am going to list all my mods for everyone to look over. If you have had this same problem or might have an idea please let me know.



Denscharger Intake
Sct Chip
Metco 6psi over lower crank pulley
Magnaflow wide open cat back.



P.S. before i put the factory cat back on I was running a Bassani off road X pipe and factory muffler. With this combo I dyno at 418rwhp and 445rwtq. after I installed the cat back I ran a 423rwhp and 413rwtq. So i put the factory cats back on to build back my rwtq. I dont think the belt is slipping because it was just replaced.

 

Did you dis-connect the battery and let it re-program the computer?

 

No I have not tried that yet. Do I need to do that everytime I change out a mod? I thought you only reset the computer after adjusting the MAF.

 

since you said you just replaced the belt, are you sure you have the correct size?

 

And if I may add, is it tensioned properly? (ie. not slipping)

 

No, you should only disconnect the battery after the following: EEC Flash; MAF change or adjustment; Changing your O2's.

By disconnecting your battery you are flushing the KAMRFx values for the long term fuel trim. If anything you were running a little rich and the car probably got a hickup.

 

yeah sounds like a computer hick up or belt slippage

 

I thought about the belt, so I called Metco and ordered the pulley that mounts under the blower. They claim it will help take out any lose tension between the pulleys. I will try it this weekend and let everyone know. I appreciate all the feedback.