Ongoing codes with 2003 Tahoe 5.3L

[rjorso]

I have been having an ongoing problem with my 2003 Tahoe 89K miles with the engine light coming on. The ironic part is that it only comes on (and stays on) during the winter (Houston, tx cold). I get the same codes every winter and they are P0101, P0171 and P0174. I have taken it to 2 different mech's, one said it needed a full tune up and injector system flush (so I had it done), the other kind of said the same thing, that it needed injector system flush (which i told him it all had been done) and it needed a new MAS changed, so it was changed as well. The codes were then cleared, but in 2-3 days, the engine light came back on and stayed on (with same codes). Also (again, only in winter when its cold) when I start the truck, it idles irratically and shuts off. It finally runs smooth when it gets to operating temp. I have been searching thru forums and I can't find anything.

What could it be, have anyone seen this before? If you have any ideas or suggestions, please help.

Thank you in advance
Robert

[MT-2500]

Work on the 101 MAF mass air flow sensor code problem.
Also check for proper fuel pressure.
MT

[brian 1]

maybe this info will help.found a bulletin for this problem.This message applies to all 1999 through 2004 Chevrolet, GMC, Olds, Buick and Cadillac pick-ups and utilities that are equipped with either the 4.8 liter, 5.3 liter or 6.0 liter Gen 3 V-8 engines. Recent warranty analysis indicates that both the MAF, or mass airflow sensor, and the MAP, or manifold absolute pressure sensor, are being replaced for a MAF sensor code P0101. The cause may actually be a MAP sensor failure causing the MAF sensor code. One of the MAP sensor’s primary functions is the calculation of the speed density formula, which is compared to the MAF sensor reading. Should the MAP sensor fail, the PCM may interpret this as a MAF sensor concern and set a P0101 code. If diagnostics are followed thoroughly the technician may find a MAP sensor failure causing this condition. In conclusion, when a MAF sensor code of P0101 is found the technician needs to verify the proper operation of the MAP sensor before concluding that the MAF sensor requires replacement. bulletin #1489128 . hope this helps.

[rjorso]

Thanks for the replies. Where could I find a copy of the bulletin??

Rob

[16th hippy]

not that it couldn't be the MAP and/or MAF, but coupled with cold weather and the lean codes, would also check out intake manifold gaskets. in cold weather cold starts, they have shunk a bit, mostly noticable in the 3-5 and 4-6 cylinder areas. get some carb/tb cleaner spray(NOT STARTING FLUID), and spray the intake on these areas, on a cold start. if the engine stumbles, there is your problem. once it warms up, the gaskets expand and seal up good. is easy enough to do. if i was a bit closer to houston, i would do it for ya cheap, but with fuel cost, would be as cheap to do at a shop...lol. but if you are mechanically inclined in the slightest, then you can do yourself. be sure to check this out before buying more sensors, and post back what you find.

[j cAT]

i agree that your problem is of a lean condition and that before buying maf/map sensors to get vacuum gauge check for proper vacuum of 21in. and look for vac/throttlebody/intake leaks. i just say no carb cleaner on rubber or electronics and wires because it is damaging............the other componet that may be acting up is a stuck/sticking open egr.............

[rjorso]

FYI - with help from different members on this forum, I fixed my problem. It was definitley an intake gasket problem. My truck has been running well so far since Saturday. And the job, was pretty easy.

Thanks agian everyone.