I installed Dynatechs with the cats and got no light,call Allen Nelson he can solve your problems or atleast get you close. I put in a new tune to go with the headers and never saw the light. He will help you.

 

For that kinda money get LS1 Edit.

 

HP Tuners

 

I don't know what all you have installed, other than the headers. But they should not be causing the SES, unless, maybe it's a reaction with some other mod. Have you check all your connections for leaks?

I never had the SES light come on and I have not changed my tuning from stock yet.

 

check if you have a vacuum leak. Ex: MAF not sealing, unmetered air coming in, etc

 

I have read in another thread that with the stainless steel headers the exhaust gases are cooler this has some effect on the o2 sensors, plus the location comes in to effect as Rick has posted above.It says this in the directions from Dynatech also.

 

Who is Allen Nelson and how do I get in touch with him?

 

Only mods I have are a FIPK, Granatelli MAF, and true duals hooked up to the headers. Never got any lights before I put the headers in. Checked for leaks just yesterday and all is good. Initially I was concerned because that O2 sensor on the drivers side is awfully close to the drive shaft for my 4X4. Checked it out after about 200 miles and no evidence it's been rubbing.

 

Something to consider:

Nelsons

Wester's

PCM For Less

 

Nelson performance, He is a tuner. I would check the o2 sensors in the cats, I had one leaking, I thought it was tight, but it wasn't.