98 379 pete

If the old owner says it was always kinda weak since he had it then its the ECM. It needs to be tuned by MR. Hanney. That will solve the problem as long as it wasn't never running that strong. Now if it was running good then just did this im sure it is another problem. Alot of those eariler cats are way under on power and almost ever time its the ECM beleive me i know ive had one do this and it is in the ECM. Some just wasn't never that strong from the factory. Im sure cat won't agree but its in the programming.