I just found an exhaust leak, it is on the connection from my EGR tube to the header, it sems to be leakin alot, could that cause problems in my tuning and be the resaon why my car runs like crap?

 

yes because the leak is before the o2 sensor and could possibaly be showing a false lean condition to the o2 sensors. I would fix it asap. does your car run rich?

 

Yeah, I would repair that ASAP. What kind of headers are you using? I had a similar problem with my Pacesetters. I purchased some high temp RTV and used that to create a better seal between the EGR tube and EGR fitting on the header.

 

I have mac headers on, and i have always noticed on my # 8 spark plug it is always balck and i see a nice gray discoloring on the egr tube connection on the header. And yes my car is running super bad switching between rich and lean. it sucks and kills gas mileage.

Thanks for your responses, i truly hope that this is all my problem and not a bent valve.
braden

 

Its more than likely the exhaust leak that you mentioned. The o2's should switch pretty fast between rich and lean. When they start switching slow is when you have a problem

 

in a few days i will be home and will do a compression test on the motor, i only think it could be a valve because i bent a push rod a while back, but truely ever since iput th headers on i have had this problem, and it has those symptoms of bouncing around fast from rich to lean.