2001 5.3L tahoe headache, pls help!

[xpo231]

Sup guys, im new at the forum thing so pls bear with me, yes i'm a nub. hehe. anyways, i've run into a bunch of problems last week and i was wondering if anyone can give me some sort of input. 2001 Tahoe. 5.3L V8, 156K miles.

1. At idle, engine seems like it's struggling to stay alive, RPMs drop below 1k and then periodically jump back up to 1-1 1/2. (check engine light on)

2. While driving acceleration is slow or no throttle response, and car will sometimes lurch back and forth.

3. More recently, there's been backfire at idle and driving.

4. Last time I drove it on freeway, going 60-65, RPMs dropped drastically despite stepping on gas pedal. Then after a couple seconds, RPMs shot up to 3 1/2 and stayed at that for a good 4 seconds before dropping again and engine dying. Had to restart engine 5 times cuz engine would die right after ignition.

5. Car would only move while driving in 1st and not mashing gas pedal or engine would die.

I've heard diff. things from spark plugs, to fuel filter/pump, injector, throttle body, etc.

I saw a recall on 01 tahoes and inquired at the nearest chevy dealership but guy ran my vin # and said my tahoe was not one of the ones recalled for fuel filter replacement. Any input would really help. thanks guys!

 

[gillarockus]

check your MAF

 

[MadMedwyn]

It could be alot of those things you mentioned. I also have another guess.

Maybe, just maybe you have a dirty mass airflow sensor (the thing with the wire coming out of it on your intake box tube going into the engine). It's very obvious where it is when you open the hood. I recommend taking that off and spraying some electrical contact cleaner on it, which will get it nice and clean. Because after 156k miles, you can bet it could be dirty. But who knows, maybe my theory is completely wrong and it won't help it all. But I do know it's easy.

I say this because my dad has a '84 Porsche 911 that would have idling problems sometimes. It was due to it having a dirty mass airflow snsor. After we sprayed it, the car idled the smoothest it ever has, and even gained power. It's worth a try. Also, fuel injection cleaner never hurts. Put a container of that in your fuel tank next time you fill up.

 

[xpo231]

cleaned out MAF put in FI cleaner

Hey guys,
Thanks a lot for the advice, I bought some MAF cleaner and sprayed it. Also, I poured in some FI cleaner into the gas tank. When I start the engine it sounds the same. The idle is at about 200-300 RPMs. When I started the engine and let it idle the RPMs almost hit 0 and then all of a sudden jumped up to 2-3K RPMs for a good few seconds before the engine died. Im about to check the spark plugs pretty soon, jus tryin to get ahold of a spark plug socket.

Is there any more electrical advice that folks can dish out? thanks.

 

[JKmotorsports]

Check into the TAC (throttle actuator control) system as well if your vehicle is equipped with the electronic throttle instead of the cable. The APP sensor on the throttle pedal could be bad, the throttle actuator control motor, or any of the sensors that the TAC system uses, like the TPS, can be out of tolerance and send wrong information to the pcm and cause erratic engine operation.
The thing with the newer cars these days is that a lot of the problems need some sort of scan tool to diagnose. At the very least, you need to know the values and tolerances of the various sensors and how to test if they are operating within specs.
Did your computer throw any DTCs?

 

[jey_]

I'd also suggest getting the Check Engine codes pulled - it'll help you narrow it down. Most auto parts stores like Autozone will do it for free.