Looking for suggestions. Had a missfire on my H2 now for a while. If you accelerate hard it goes away. Changed plugs, leads and nothing. Fitted 8 new coils this morning, and its mostly gone away now. Cruised about 100 miles smooth as silk, but its still there intermitently. Slight hessitation more than anything now.

I know my Cats are completly shot. Could this be the cause?

Any Help is appreciated...Its driving me mad now.

Jay

 

how do you know your cats are shot? thatswhat id be fixin imo

 

1) My exhaust is in V bad condition, very rusty.
2) Car developed a rattling sound, tracked it down to the cat/cats.
3) Rattling sound went away, meaning the insides broke down/got loose, as they do, then got blown through the exhaust system, so they are now essentially empty lol.

Im waiting for have a new custom exhaust made, iv got some new manifolds and when its made il have new sport cats. Someone told me at some point hummers dont run well without cats so im hoping this is the problem.

 

Yep I would go with the Cats. I had one collapse and before it went it was giving the same problem. 1 replaced and it was ok, other is on its way out now.... dammit

 

I have an 03 H2. I had lost power and was getting a multiple missfire code. I replaced plugs, leads and two coils. My cat convertor was replaced and I put a flowmaster 40. It was a combonation of things that went bad at the same time. Now it runs great!