98 Z71 5.7L losses power at 3000rpm

[prozaxxx]

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

[corning_d3]

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.

[prozaxxx]

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.

[corning_d3]

Glad to hear it's running good!

[Riche]

"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

[corning_d3]

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

[Riche]

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.

[corning_d3]

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

[Riche]

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.

[618stanley]

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

[Riche]

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.