I have a 03 Z06 and I just put the stock manifolds and cats back on after having LG long tubes with-out cats. The car ran fine with the LG's and no cats but when I put the stock system back on the car started bucking or acted like it was loading up with fuel at slow speeds when under a load. It did this for about 15 min. and stopped. But now when I try to accelerate hard the car starts to buck ( seems like its loading up with fuel and you can hear it popping in the exhaust system. ) I have unpluged the battery for the night but I dont think its going to help. If anyone has some input I would Appreciate it.

 

Sounds EXACTLY like you have an engine miss fire most likely related to a plug or wire issue. I would make sure that:

1. The plugs are not cracked. (Very easy to do)



2. A wire is not completly on the plug or coil.

3. A wire is damaged. They should read 250-750 ohms end to end

See if your check engine light (CEL) flashes when your exhibiting the problem.

BC

 

Number one cause after messing with header / exhaust replacement is cracked plugs.....followed by a close second is O2 sensors crossed, but thats usually only when putting headers on, since they are real close. I dont think that you can cross them with stock manifolds.

 

thanks i will check that out.

 

Since you didn't have catalytic converters with the headers, were the O2 sensors tuned out?
Would that result in the symptoms if not re-tuned for oem?

 

not sure about the 02 sensors. I did have the check engine light when i first put the lg's on but the battery died and when i replaced it the light never came back on. I have the battery disconnected now and will try the car in a couple of days to see if it helps anything. But I think the cracked plug sounds like a good posibility. I will let everyone know when I find out!

 

Check the plug wires, be sure the coil boot clicks twice, slip a nylon wire tie down along side the plug wire where it enters the boot to allow trapped air to escape.

Charlie

 

knock sensors can also cause this

 

It was the number three plug! Thanks for all of your help.