The Ignition has been changed on it (Spark Plug, Wired, Coils and ICM) and still the same and as I say no lost of power and no explosion in the exhaust (Use to have it before changing the ignition)

Got it only since I've put an high flow Catalyser in addition of other mods (my previous catalyser was dead)

 

And my reprog of the ECU made this summer is making my engine to run a little bit too poor than the original ECU

 

I will cleanup & check everything I can, after hum ... the ECU reprog has been done during the hot summer so may be the something related to the air coming in the engine (better and colder). the flow is higher now since I've change a dead cataliser nearly dead by an high flow, the engine is acting differently to compense it.

 

If I may ask did you say you changed the Catalytic Converter to a High flow?

 

Yep why ?

 

Just asking, you said your engine is compensating to the high flow? The cat converter is a post-engine exhaust "filter" using a catalyst or matrix, the high flow allows for a better flow coming from the manifold,but usually only helps with the install of headers

 

need to re tune it.

 

My 1999 Camaro v6 3.8 sounds just like this, but mine is throwing a Cylinder #4 misfire code. I like it but I also don't cylinder wall scuffing.

 

Look after Spark Plugs, Wired, Coils and ICM.It's happen to me to have e defect ignition coil, who was creating misfire and kill my catlyser as I wait too long.

For me My car is still running like that but I've change eveything and the garage where I'm doing the maintenance didn't find anything, I have no loss power and still driving it and doing regular maintenance

 

Almost a 3 old thread, think he's fixed it by now.