Bogged acceleration, MAP sensor??

I drive a 2001 xtreme 4.3L auto. I am having very bad acceleration response when I try to punch it. Even when I put it into neutral and gas it, the blazer boggs alot. I can only go at normal speed while pressing the gas pedal down slowly but only to about an inch and a half down. Then when I try to accelerate to pass someone it drops into gear like its going to take off but doesnt go anywhere, the engine is screaming, then when I slowly depress the gas about that 1 1\2 inch mark it finally goes. I had taken it to a trans place, they said it the trans was fine. Got a tune up, wires, plugs, distributor cap, it ran strong after that but eventually went back again. I cleaned the MAF sensor and nothing. I had the trans filter replaced, ran fine, then back to its ****ty response. Certain times though the blazer will run just fine, but most of the time its crappy. I ordered a new MAF sensor and a mAp sensor. Does anyone know where the MAP sensor is in the blazer. Does anyone else have this problem???

MAP sensor is located on the passenger side of the plastic upper plenum alittle behind the throttle body. Remove the electrical connection and pry it out of the plenum.

thanks, I will try it and hopefully it works.

the map sensor will throw a code if its malfunctioning. do you have any ses lights?

theres no code, the whole time it drives crappy and no code comes, the only time a code came was when I layed on the gas and tried to accelerate, left it for a few and the check engine light started flashing, then I let go, and drive normally and it stops flashing for about 15 sec after.

Just because the check engine light doesn't illuminate does not mean that there aren't any stored codes. Many DTCs do not trigger the light. And many of these DTCs may not be read by some of the scanners used by Autozone, Advanced, etc.

I agree the code may not necessarily display, but from experience when my map sensor went out the truck only hesitated during heavy loads on the engine. Normal driving wasn't affected at all. I'd just be cautious thats all electrical parts are hard to return if they don't fix your problem.

ya that seems logical. I guess it would be a good idea to check it out, got my MAP sensor today, so Ill install it and see what happens. Ill post the results, thanks guys

hellz yea, I changed my map sensor and it seemed to have done the trick,
everything is back into flow, shifting, power, idle, and everything. Thanks guys for the help!

glad to hear it!

tell me about it, It was such a headache tryin to figure out the problem, calibration, programmers, nothing could figure out what was going on. Then changing the MAP sensor which only took like 5 minutes did the trick, dood I am so relieved, now Miss Jane and I can have our lives back. :)

Well now. I think I'll have to change my MAP when I do my lower intake manifold gaskets. I have a slight bog in my acceleration that has been there since I purchased the truck and have done everything under the sun (tuneup wise) and it has gotten MUCH better, but I feel that it should have more get up and go, especially when passing. Can't be too expensive and I know how easy it is to remove (hint - no tools required).

Good deal!

Ya I agree, the same with mine. It was more long lasting and increased while time passed. It was like 40 Bucks, but u can always return it if it doesn´t work. I mean, something so little made so much difference, no mechanic couldn´t figure it out, they kept sayin it was my Transmission. Reading the forums def helped.

Hey, I just want to say that this forum FKN rocks!   I had the exact above problem(which my mechanic didn't even know what was wrong with my Blazer - he put a new fuel filter on, which didn't do ****).  Came home and read this, went to Advance($63 for the sensor), and I'm back in business.
I'm a huge fan of this site!
Thanks.

Hmm, this sounds very much like the problem I'm having with my new to me 99 Jimmy.  Question- did you notice if your engine was running rich during this?  I've noticed lots of black residue in my tailpipe, at first I thought it was the O2 sensor(s) but I'm not getting any Check Engine light...