Ive been having an issue recently with my TA. The car has been bogging out, idling low, and becomes unresponsive and then acts fine again. This will happen when I start the car sometimes, although sometimes it will happen while sitting at a red light or even cruising at low rpm. For example ill be cruising at 45mph with my foot barely hitting the throttle, and then ill go to hit the throttle and the car will feel like it was missing, with no power and a rumbly idle, and then ill put my foot into it and after a few seconds it will just take off. The weirdest part about all of this is that theres NO CODES! im going nuts trying to figure this out, and it doesnt help that my gas mileage is alot worse now (got 100miles out of 3/4 of a tank). Anyone have any insight here? Help is appreciated
__________________ 1999 Trans Am - Navy Blue Metallic: 18" C5 Thinspokes, SLP Lid, Custom CAI, Konis, Ported & Polished TB, LPP Stainless Headers & ORY, Level IV 4l60E, Factory 3.23s, 160* Tstat, TB Coolant bypass, Magnaflow catback
tune up done recently ie, plugs air/fuel filter? If you suspect it to be the maf, unplug it to put the computer is safe more, it will bypass the maf and go to a set map for driving. My buddys car did not have a maf code, but it was bad and drove like shit.
Any other recent tuning been done, or is this just out of the blue?
It could be that those headers have got your O2s all
sleepy, making the PCM false-trim to pig rich at idle
and low cruise. Throttle will heat them up and let them
trim back, some, until they go cold again.
also another thing to test is your map sensor.. of you have a fluke meter test the sensors. they should read 4-7 ohms across them.. fluke meters come in handy for testing sensors first before you go buy any of them!
__________________ Carl S.
Mike F.
SFEngineering
(832)-216-1143
It could be that those headers have got your O2s all
sleepy, making the PCM false-trim to pig rich at idle
and low cruise. Throttle will heat them up and let them
trim back, some, until they go cold again.
I installed a set of Pace setters on my 02 Trans am and now I'm throwing a PO153 code saying the back 2 sensor 1 slow responce. Well I replaced the O2 with one of the leftover sensors from the conversion to LTs. After a couple days the code came back. While I was sitting at the drive through yesterday my eyes started burning and I realized that it was the car running rich.
Im having the same problem as you are, but (supposly) its misfiring and i dont think it is its not bringing up any codes. So help me out, It gots a cam, LT headers and ls6 manifold on a 01 ws6. I thought it was just the tune so i sent it in to TUNEDBYFROST. Got a mail order tune and still ran bad it surges like how u say it then it runs fine the next second. Its not the plugs Ive changed them and also changed the wires and still ran bad. Drove 100 miles then checked the plug and it was black and the electrode was a bit red,brownish color. COIL??? I dont know anymore. I drive it and its surges for half a second and then runs fine!!! But Ive noticed that when it surges The service engine soon lights up but then goes away. So Im wondering to my self...WHAT THE HELL IS THE PROBLEMS??? The tuner told me it might be a HUGE manifold leak or misfire. So I thought about what I did... I drilled a hole a bit bigger than the one on the Throttle body and hes telling me that might be it. Because he tuned it for so much air but that the hole is giving it more air than what its suppose to have SO DO I NEED A NEW THROTTLE BODY??? The tuner said its not the tune that its the car so UMMMM CARS FUCKED UP I GUESS
I've seen holes drilled in the TB to help maintain idle with a BIG cam, but it doesn't end up doing much because your iac will detect it and adjust the idle accordingly. I took a look at my o2s and it turns out one of the wires is a little burnt from rubbing on my headers. I'm gonna change my o2s and see what happens....
sounds like the O2 is bad. They dont get "sleepy" they get slow, so instead of constantly reading exhaust they take a little longer to "report" back to the PCM, time for new ones... whats your mileage?
the ones on my truck lasted about 90k and got tired
__________________ http://i271.photobucket.com/albums/j...uck/720092.jpg
LQ4//Lunati//241's//80e//LT's//Tuned? R.I.P.
Your heart will live on...
'68 C-10 RCSB-350/4L60e/LTs/Slow-SOLD
'04 Gix 6-Passion not fashion
'99 T/A T-56//LS1//Fun
I never had this code (PO153) before I installed my headers. The car only has 50,000 miles on it and I replaced that O2 with one of the ones I wasn't using and boom...........samething.
Heater power is limited, you need the sensors to be
good and hot, header surface area to shed heat is
much greater and the sensor further from the source.
Cooler is slower, but at some point you just get no
output at all. That's sleepy time.
I bet there's a small market for heater step-up power
converters (ala boost-a-pump) that would push up
heater voltage. Maybe with a close-in temp sensor
so you only do it when needed. I do not know how
much room the heater has, to be overdriven, but if
it's too cool there's that much more margin before
it melts.
The "vette rears" are purported to have higher heater
power. I got the switching codes when I swapped
to headers with NGK 'vette rears, but still have OK
switching waveforms.
There's a continuum of screwedness that goes with
outside temperatures, header coatings, engine load,
heater power and all kind of things.
Going crazy with this, experts come in! 
Tim's Automotive Center
