Computer Won't Hold A Tune...HELP!!!
 

Computer has been tuned 3 times on the dyno and each time after about a week it starts to richen up the car bad. Last time it was up 20%! The car is an auto with a six speed computer b/c of a 2004-R tranny. Has anyone had a problem like this? Any help will be appreciated. Thanks.

You CANNOT get a proper full tune from just using a non load bearing, static dyno.

For one the engine conditions while doing a pull are not what it does 99.9% of its life and 2nd on a dynojet your only using about 4 or 5 of the 24 fuel trims so the tune NEVER sees most of the engine conditions so within a short time all those other conditions will delute/effect what little changes they did via the dyno.
I suggest you go to a real PCM tuner that adjusts for all driving conditions for once all fuel trims are adjusted properly they pretty well stay within a few % of where they were adjusted to.
The last tune I did on my car was over 1 year ago,
I monitored fuel trims for that year and they still are locked in where I adjusted them.

would having an air/fuel gauge on the front O2 sensor screw up its reading for the computer?

If your long term fuel trims have not been compensated for/tuned correctly you will have varying amounts of fuel being added at WOT.

Car is awesome for a while after the tune then slowly it goes away. On hot starts it loads the motor up and tries to foul the plugs. Everyone I've talked to hasn't heard of this before.

Team ZR1 is 100% right.. You can not just tune a car on the dyno without street tuning the Fuel trims!

it drives good on the street for a couple weeks. I don't understand why one day it just decides to run like crap. So everyone is thinking its a tuning problem and not the PCM not holding the memory?

It is most likely not tuned right for closed loop
and "learns" its way back to what it "thinks"
is right. Then if it's correcting positive, this
ends up corrupting the WOT as well.

Just another reason to seize the power for
yourself instead of hiring it done (or half
done). Some of this stuff takes seat time
and road logging to uncover, understand
and fix.

Maybe you should think about what on the
car could account for a bad lean error. It
may be a tuning problem, but it all starts
with something that feeds bad data, or is
not living up to its computer table model's
expectations. What are your aftermarket
mods?

hooker LTs and y-pipe, exhaust, lid, pulley, TSP 231/237 cam, 918's, retainers, ported oil pump, ported TB, 2004-R Tranny, 3800 stall, Hammer Shifter, 3.73 gears, and TNT F1 Kit. I think that's most of it.