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Discussion Starter · #1 ·
My 04 Envoy Xl I6 had a code 172. I took it to GM They cleared the code road tested it and said that everything is running close to spec. They told me that the second o2 is slower to respond, the maf is reading 40g/s less then spec at full throttle and he can hear a slight exhaust leak somewhere up front but can really tell where on a quick check but really doesn't sound that bad yet. The prob I have is it sometimes stalls at stop lights but not all the time. It mostly feels like when I press the gas pedal it doesn't respond the way I would think it would at where I have pressed it. He told me to clean my maf screen which made me laugh because I don't have one. Poss I got bad gas with water was another suggestion he had. Is it poss that my Map sensor is going or what?
Paul:crazy:
 

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2003 gmc envoy_slt
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:tiphat Welcome :tiphat .Have you cleaned the throttle body lately? It's a known problem. While there is no guaranty, cleaning the t-body is usually needed about every 30-50k miles. This will also remove a dirty t-body as a source of your problem.
 

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Discussion Starter · #5 ·
Ok I cleaned the TB. It was very dirty with gunk. That made a big dif on the stalling and the code hasn't came back but now I have new codes that came a couple days ofter. code 171 and code 1133. Now what?
 

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Did you disconnect the battery while you cleaned the t-body? Remove the t-body or just sprayed while it was still on the engine? P0171 is a lean condition (The t-body is clean you're getting more air) The P1133 is O2 sensor. It will take a few heat/cold cycles to retrain the PCM for the new conditions.
 

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Discussion Starter · #7 · (Edited)
I took it off the engine to clean. I didn't remove the bat cable when I cleaned the TB. I drove it on a long trip about 1000 miles. I had to clear the codes everytime I got gas. I'm back now so now I have time to fix what ever is going on. So a good start would be to remove the bat cable and reset the comp? I also for got to say I was towing a 18f travel trailer
 
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