Hesitation problems

[Sentax]

Hi all,

I need some assistance on an issue with my 1999 Silverado. I have a hesitation problem that only seems to accure after the truck was just recently started and I take off for the first time on the road. I will hit the gas slightly and the truck will begin to take off but will not be responsive on take-off like it use too. If I let off the gas some times and then re-apply the gas it will seem to work itself out and then any take-offs after that seem normal. Sometimes I will put the gas to the floor and the truck will still accelerate slightly but will not attempt to just get up and go.

I have done oil maintenance on schedule all its life, just did spark plugs 3 months ago. Had fuel filter changed 3 months ago.

The correction of hesitation after the first time seems to me may be a bad sensor somewhere giving wrong information and the computer corrects itself and all is good.

Where should I start with fixing this issue?

Specifications:
1999
Silverado
4X4 z71 Ext Cab
5.3L V8

[maxwedge]

Welcome to AF. Check for pending codes, clean the MAF, no cold air inatke right? Check fuel pressure also, need 60-65 psi.

[Sentax]

Thanks for the quick reply and the welcome.

No cold air intake is correct. Recommended?

Check for pending codes. I have no way of doing this without involving a technician/dealership correct? I'm trying to diagnose this as much as possible and trying small things before breaking down and bringing it in. I'm use to working on my own things I guess.

MAF, Mass Air Flow? How would I check this?

Fuel pressure, Again, how can I do this without technician/dealership?

I apologize for being completely incompetent about this. I bought this truck semi-new and haven't working on a vehicle since my first vehicle which was an 80 Bronco and the tech of these two vehicles are completely different as you already know. All help is much appreciated.

Edit:

Also I want to note this problem doesn't accure with the vehicle in Neutral. I can rev the engine like normal in N. Just when I'm in drive and the engine is under a load this accures.

[wrparks]

Any auto parts store should be able to check for any codes that are being set. advance or auto zone work for me.

[gremlin96]

I am not shure if you truck has a distubtro or not. if it does a quick look under the cap should let you know if mosture is getting under it.

there bad a bout cracking.

[firedawg81]

I know you wont want to hear this but my truck did that for the past 8 months and I couldnt figure out what the issue was. I replaced the Mass Airflow Sensor and I had the tranny and rear diff looked at. Noone could figure out what was doing it because it only did it when it was cold and it never threw any codes. Christmas day I was driving home and my truck finally sputtered and died for good. The fuel pump finally took a dump and thats what was causing the issue the whole time. The fuel system is notorius for causing issues and it wont throw codes. I would really look into dropping your tank and replacing your fuel pump. My symptoms were exactly like yours and I spent a whole bunch of money replacing other items... I even took my $200 K&N cool air intake off...

[maxwedge]

You need access to testing equipment here to properly diagnose the problem or uneccessary parts will be flying around, naturally a FP gage is required to check the FP, a full scan can pickout other issues, AZ cannot do this. You could clean the maf sensor wires, very carefully, with CRC maf cleaner, as an experiment. No, cold air intakes are a non-issue here, they can contaminate the maf due to over oiling them.

[firedawg81]

Yeah his symptoms sound EXACTLY like mine though. I would really focus on the fuel pump if I were you. I have the same year and model truck. Mine was tough to test because it only had issues about twice a week. Eventually though you'll most likely figure out the problem when it gos full blown..hopefully your not in the middle of nowhere when it does.

[Sentax]

Thanks for your replies.

I was thinking it may be related to the fuel pump. But wasn't quite sure. I just got back from vacation yesterday and am going to take some time to clean the MAF sensor today and find out my results.

Friend of mine replaced his fuel pump in his Silverado and told me he had to rest the tank on his chest when he was doing it himself. Of course it wasn't full of gas .

Well I would like to try the most simple things first and see what results I get. I'll start with the MAF sensor.

Do technicians have a FP pressure testers readily available? How much would a typical test cost? I'm sure he would like to get business for the replacement if it is bad also.

Well, I'll post back on my results with MAF.

Thanks

[rjeffery]

You can buy one from almosy any auto parts store. I got mine from Autozone for around $50.

It may be better to buy one than to have a one time test done. That way you can play around with different things and see how the FP responds.

[maxwedge]

Do not do this tank pump on your back, please!

[Sentax]

Originally Posted by maxwedge

Do not do this tank pump on your back, please!

Trust me, I will not be doing this. I don't have the right equipment to do this properly. Was just stating that my friend did it that way which shouldn't of been done like that.

Thank you for the concern.

Update: I cleaned the MAF sensor with Qtip and some alcohol (Didn't have brake cleaner). Carefully wiped the sensors off. They were very dirty considering their size. I re-installed and went and filled up my tank. My performance seemed to be there the whole time on take-off after start-up. I'm going to go wash it now and we'll see how it does through all the stop lights there .