Iv_z28

I already described the problem a while ago and here is the development.
At idle LTFT's are ~3-6%.
At open throttle (doesn't even have to be WOT) LTFT's go to 25%.
I believe I fixed the fuel issues - changed the fuel filter and run some GM fuel injector cleaner - the fuel pressure is 58-60psi and appears to stay close to that at WOT, not less than 55psi.
I do have ported MAF but before I start to play with tuning I'd like to make sure there are no mechanical issues. Also the problem developed long after I ported the MAF. So, could those high LTFT's be in anyway related to carbon build-up? If the injectors are clogged with carbon, is there an easy way to know that and is that possible? Could it be that top end cleaner could also clean my O2 sensors ? - I get P0137/0157 all the time, no other codes, I'm thinking perhaps it may serve as an indication that something is not right with O2 sensors, including the front ones? I plan to change my TR55 shortly and I'm trying to figure out if it would make sense to run some top end cleaner through the engine first? (The car has 75k miles). Thanks for any advise.

WicketMike

iTrader: (13)

i would change the 02's and put a stock MAF back on and see what happens then

Iv_z28

Well, my stock MAF is ported, so it would be easier to get MAFT, which I plan to do next, and changing O2's just to see what happens is not quite my style. I'm more interested in knowing if $5 top end cleaner could have any effect of the situation or it's stricktly for KR issues (which I also have, but I'm also very lean, I guess...).

J&JsTA

I ported the MAF on my A4 and had the same results but only at the track .... I would stick with what has been changed as the issue unless you can think of anything that would cause you a vacuum or air leak after the MAF and before O2 sensors .... could try the cleaner, won't hurt ....