Drew24

This issue has been going on for a good year now. I have replaced the opti, plugs, o2 sensors, plug wires, and icm. I have no codes and fuel pressure is perfect. I just recently got it dynoed and got 234 at the wheels . I'm pretty sure there is something wrong with her because I get about ten miles to the gallon and when I'm driving it I let off the gas and it boggs down and sometimes backfires. I even went so far as to take it to the dealer to see if they could find anything in the pcm that could point me somewhere. They said the tune looked good and couldn't find anything. The mods I have are bbk headers true duals k&n mad opti 4.10 and a tune. Any advice or anything I can check? Could it be a clogged cat?

djjab57

iTrader: (17)

Could be a clogged cat, Look at it at night see if its glowing. That would be a dead give away but not the only way to know

boostedlt1

iTrader: (2)

fuel pressure regulator could be leaking and you're getting excess fuel into the intake manifold via the vacuum line.

lncboytre_d

Check for an exhaust leak. I had a leak before my cats and when I let off the gas it would back fire
Hope it works out for you.