have a weird problem when i accelerate hard and it hits 3000rpm it loses all power and hesitates. i've been searching the forums and haven't found anything yet. any help i would be greatful

thanks

98 chevy z71 4x4 5.7L 127k

Your about due to replace the fuel pump if you haven't done so already, so have the pressure and flow checked. Changing the fuel filter is a good idea. I've cleaned many GM MAF's and gotten rid of drivability issues, also.

Thanks alot for the info. I changed the fuel filter and cleaned the maf and. all i can say is thanks again. i bought it used and didn't realize how much power i was missing, but no longer thanks again.

Glad to hear it's running good!

"cleaned many GM MAF's" I just wanted to know how can you tell when they are dirty? Are the noticeably clogged (i.e. the holes in the screen)
I guess I want to know if the can they be dirty but not obviously clogged.
If so how doe you clean them.

Thanks

I was referring to the wires inside the MAF. The best thing to use is something that doesn't leave a residue, like tv tuner cleaner or circuit board cleaner. I used 70% alcohol 'n' a Q-tip. The MAF screen can be sprayed clean, too. Make sure it's all dry before re-assembling and starting. If you really want to get it clean, you can seperate the 3 pieces by removing the allen bolts. All the pieces only go back together one way, so mark all 3 with a paint pen or sharpie before dis-assembling

Thanks for the info. Mine is hesitating almost like a bog, and then it clears out and accelerates fine above 3000 rpm. Guess I need to check the fuel pressure. I bought it used and it has been running like this for 2 years, one would think the fuel pump would have died by now but who knows. I had to change the cats, but that only helped me a little as far as smoother throttle response. I am willing to try just about anything.

My blazer was doing that until I cleaned the MAF..

Well I never would have guessed it. That sucker didn't even look dirty. It made a very noticeable difference. I still have a little bit of something going on but I guess I can figure that out one day. Thanks for the advice, Very good information for anyone with a 96-99 vortec with high miles and a previous owner that didn't take the words routine maintenance very seriously.

Interesting helpful info...... where is the MAF located ? I can figure out the rest by the post's. Any "by the way's" when I clean the unit ?
My unit sit's there at 3000 rpm as well. New to Chevorlet, old to Ford's. I saw the light however !!!

99 K1500, Z71, LS Package, 5.7L, Old Body Style.

Thanks

It is on the intake tube between the air cleaner box and the throttle body of the engine. It has a quick connect plug to it when you pull it off it will have a honeycomb screen in it. On the opposite side it will have 6 little bars with 3 resistor looking sensors running between them. If you are going to try to clean them be very gentle. The rest of the MAF is plastic and aluminum.