2002TransAmWS6

Hey,

could someone give me a few hints on what to look for with these codes ?
2002 TransAm, A4.
The long-term-fuel-trims were at 25%, with STFT still at +18%, and I got those codes. I disconnected the battery and tightened a clamp around the MAF, LTFT dropped to around +3% at idle, but the more RPMs I have the higher they go.
Max is around 18% when going 130 mph. The weird thing is, I drove the car a few months, and there were no codes, nothing. Then suddenly a week ago, P0101 showed up, MAF. But I haven't done anything.

Can't find a vaccum leak, O2 sensors seem to be ok, fuel pressure is ok, fuel filter is new. No leaks with the LS6 PCV-system, plugs on rear of valve covers in place. Intake manifold pressure shows 9.4HgIn at idle. Unfortunately I can't get much sensor data with my notebook and scantool.net, just the generic OBD-II-stuff.

Today I unplugged the MAF, and then the LTFTs are fine, and the car drove like a completely different car, and it felt like it suddenly had a lot more horsepower and I even thought the transmission shifts a little nicer than with the MAF plugged in. It never drove like this before, so I guess the car already had the problem when I bought it in Texas a couple of months ago and then had it transported to Germany. As far as I can tell, nothing has been changed on the car, everything stock.

What can I do to find the cause of the problems ? Is there any way to really check for a vacuum leak, like checking the intake pressure or something ?
I tried spraying brake cleaner around the intake, nothing happened.
If there was a vacuum leak, shouldn't the LTFTs go down with more RPM instead of going up ?
Should I just replace the MAF ? Can I drive without the MAF ? Disadvantages ?
As the problem is on both banks, I can't believe that both O2-sensors go bad at the same time. And with the MAF-code also being set, it really looks like a vacuum leak, but I have no idea how to find it. I have some kind of surging sound near the throttle body, but I think it's just the air going through inside, not from outside in.

Any help is greatly appreciated.

Thanks,
Sebastian

LS1-450

iTrader: (33)

Sounds like a bad MAF. When dissconnected, the car runs in speed density. This is why it ran so well. Replace the MAF. Can probably find one @ a salvage yard for $25.00. Just tell 'em the year & model & they will print a list of vehicles that use the same MAF.

Dissadvantages of running without the MAF (with current tune) is that the car may & likely will run lean. If you were able to run an auto VE without the MAF & then modify the VE tables accordingly, you'd be alright until major weather/temp changes occur.

Replaced MAF should correct the problem.

Oh......just saw that you are in Germany. Won't find many MAF's in salvage yards there. Will probably have to buy a new replacement.

Killer_Bluebird

iTrader: (23)

If you are using a K&N or similar filter you may just have an gunk up maf. Try using some MAF or Electrinic Contacts Cleaner. Spray the heck out of the sensor wires, but do not touch them, some have used Q-tips to clen them but you have to be majorly carefull. If that doesn't work then order the maf. But it is worth the shot trying this for a couple bucks.

2002TransAmWS6

Thanks for your help guys, I found the problem today.....

Kind of embarrassing I didn't find out myself......there seems to be some kind of gasket in the stock-air-filter-box, 2 very small parts of that gasket were sitting on the MAF screen.
I never would've thought of that, I replaced the air filter a few weeks ago, saw that gasket and thought about replacing it, then forgot it, and well.....

But I'm just glad the problem has been solved.

LTFT are perfect again, 0%.