hey, i'm new to the forum... and i'm also new to this kind of problem... when i first bought the truck, the service engine light was on... i had it checked out and it was a catalyst problem... a few weeks later i had it checked out again, and now it's a catalyst, misfire, and maf or vaf sensor problem... i had my catalytic converters cut off between the times i had them checked out.. could that be why all these new problems have arose? i can't figure it out... i figured changing the spark plugs would fix the misfire problem.. but it's still showing up... please help?

 

Were there any sensors in the cats when you cut them out? Ususally there will be the O2 sensors in the cats.

 

There's the O2 sensor in the cat, the MAF might possibly have problems with a larger air flow which removing the cat and installing a D/E would create.

Inevitably, you will want to have your PCM reprogrammed with your new exhaust specs, and that will probably reset your MAF, but you'll have to discuss how to handle your 02 sensor with a muffler shop.

 

1. Clean MAF with MAF sensor cleaner
2. Spray soapy water on spark plug wires and see if there's any cracking noise coming (leaking wires)
3. Replace fuel tank cap with vented one ($7 Shucks, made in USA), and blow system through with a can of Seafoam at HWY speed for about 30-40 minutes.
4. Disconnect battery overnight to clear ALL codes stuck in ECM.
see what happens. Total cost - about 12 bucks.