i'm getting a slight backfire right around 25-2600 rpm mark when i drive the car at the same speed and amount of pedal for a certain period. it mainly happens when i let off and get back into it. i've tried playing with the fuel map to pull it out but i still can't figure it out.

any suggestions?

 

If you make fueling changes, and they don't help, then try working with the timing. Backfires are normally from being lean or too much timing.

 

Grumpy, yes i would agree with that, but the thing that i noticed was this satement, possibly he needs some pump shot work.

the other thing that i noticed, was he said it is after he holds the throttle steady for a couple of minutes, i am thinking hi-way mode, and possibly being too lean with too much timing in hi-way mode.

(note: I am moreso asking for confirmation on what I noticed, not so much giving advice)

 

that would make since seeing as highway mode it does run pretty lean. however when i added more fuel it did that much more of a backfire at that point.

 

exhaust leak?

 

I just had the same problem. Spent a week trying to tune it out. WB showed fuel good, kept pulling timing out, no good. After severely overanalyzing the problem, I changed the spark plug wires. Problem fixed. Put the timing back in and it runs great. Sometimes we overlook the basics.

 

new plugs, new wires, new everything electrical in that area. good exhaust too.....

 

Did you ever get this one figured out?

 

combination of TPS sensor (main) and timing was slightly off.....tps was the large one though. it wasn't that it was bad but it was "catching" if you will on my accel TB. seems that the blade once it moved was actually carving itself into the billet and sometimes sticking causing all sorts of bad things.