legacycentral bbs

Seems like when I check my fuel trims. Lets say 1-7. Sometimes it is consistently increasing so -5.5, -5, -4, etc etc. Yet sometimes they are all over the place like -5.5, 5, -1, 14. How does that happen? Tried replacing the o2 sensor same sort of symtoms but I didn't reset the ECU this time I did and it seemed to be fine after driving around went back to like -3, -2.8 , -1 etc etc.

What would result in this? Exhaust leaks? Could a bad fuel pump not given consistent pressure create a problem?

Fuel economy is definitely not nearly as good as it was when I bought the car which really sucks

Octane factor now stays at 100% all the time.

Being most don't know about the various fuel trim tables, you're not going to get very many/educated answers

I believe the stock fuel trims have a range of -20/+14.7. Do you have the stage 2 v3 chip, which has a -50/+50 fuel trim range? Here are a few random examples of my trims over the past months... octane factor bouncing all around. Until your octane factor is a solid 100%, I wouldn't pay much attention to the trims, as long as they're all within reasonable ranges, until it completely learns.

im back to stock and covered the knock sensor wiring with high temp rtv. Octane factor always at 100%. Replaced my exhaust manifold and i think this one is also leaking at the crossover.

Oh yea, forgot to mention that stock fuel trims are in the negative range, while with the chip they should be positive (per mike @ rev in various threads over there).

Replaced the crossover pipe car seems different. Next will replace the fuel pump, THEN if needed injectors.

Update popped in some other injectors I had, sprayed a CRAP load of seafoam still getting + fuel trims as high as 14.... SO I am thinking time for a fuel pump Octane factor always 100%, and no knocking, and boost is there just not as much power as I would expect.

Fuel trim with the stage 2 chip is +14.7 for a few cells? If so, Mike has an updated chip that raises the trims. I bet your idle bounces after sitting for a while too...