01bansheefox Posted June 4, 2006 Report Posted June 4, 2006 I know this is pretty impossible to pin point on here without seeing it yourself but i thought I would give it a try. I have a 97 tahoe with the 5.7 and for some reason it will only take off when i barely give it gas, if i push the throttle more than like 1/4 or 1/2 way it just bogs down and wants to die and drops to like 300-500rpm. It will idle fine but if i give it alot of gas or anything past 1/4 quickly it drops the rpm and coughs and splutters. Thought it might be the fuel filter but that wasnt it. Quote
RIPPEN Posted June 4, 2006 Report Posted June 4, 2006 Just a wild guess... Maybe throttle position sensor? RIPPEN Quote
bansheefreak Posted June 4, 2006 Report Posted June 4, 2006 Just a wild guess... Maybe throttle position sensor? RIPPEN id say that too... but might check air filter fuel filter...might be a restriction... might also make sure fuel line is not collapsing whenyou accelerate... Quote
DaFish Posted June 4, 2006 Report Posted June 4, 2006 is your check engine light on? its either your mass air flow or your TPS (Throttle positon sensor). if your check engine light is on go to autozone and they will tell you whats wrong. Quote
01bansheefox Posted June 4, 2006 Author Report Posted June 4, 2006 i just replaced my fuel filter and i even took my air filter off to get more air flow but still bogs down big time . Autozone does it for free? And my check engine lights goes on and off. Quote
banshee370 Posted June 4, 2006 Report Posted June 4, 2006 I cant remember if the 96 or 97 was the cut off for the vortec motor. If its a vortec, then it has a plastic upper plennum (intake manifold) It is very common for the fuel pressure regulator starts leaking. (found under the intake) Or the fuel pump. I had the same problem as you described with my 99 tahoe and it was the fuel filter. Not long after my fuel pump died. The first thing I would recommend you to do would be to check the fuel pressure at the fuel rail/intake. Have you ever checked your intake gasket? How many miles on the truck? It is VERY common on the vortec's to suck the intake gasket at the back. One other thing to check would be the catalytic converter. If its clogged then it could cause the same symptoms as you stated above. When was the last time it was tuned up? (cap, rotor, wires, plugs) check out www.fullsizechevy.com Lots of good info there Quote
RIPPEN Posted June 5, 2006 Report Posted June 5, 2006 Asked a friend tonight thats a auto mechanic and he said besides the TPS he would also check the mass air sensor or fuel pump as stated above.. RIPPEN Quote
01bansheefox Posted June 5, 2006 Author Report Posted June 5, 2006 I just replaces the TPS took about 5minutes and so far the thing revs good and doesnt bog what so ever, but i will find out tomorrow when i drive it to work. As for the fuel filter i replaces that last night didnt fix it and also my fuel pump was replaced a few months ago. If the TPS doesnt fix it i will check into the Air Mass sensor but i think the TPS fixed it , thanks guys. Quote
dirtplay1975 Posted June 5, 2006 Report Posted June 5, 2006 yes autozone can check the codes, and it is free. we do it all the time here Quote
Wallrat Posted June 5, 2006 Report Posted June 5, 2006 Usually the TPS doesn't even need replacing. You just gotta hose it down w/ some throttle body cleaner and its good to go. I've seen it happen more than a few times. Quote
floyd398 Posted June 7, 2006 Report Posted June 7, 2006 (edited) It is very common for the fuel pressure regulator starts leaking. (found under the intake) Or the fuel pump. I had the same problem as you described with my 99 tahoe and it was the fuel filter. Not long after my fuel pump died. The first thing I would recommend you to do would be to check the fuel pressure at the fuel rail/intake. Have you ever checked your intake gasket? It is VERY common on the vortec's to suck the intake gasket at the back. One other thing to check would be the catalytic converter. If its clogged then it could cause the same symptoms as you stated above. When was the last time it was tuned up? (cap, rotor, wires, plugs) check out www.fullsizechevy.com Lots of good info there Good advice from banshee370. actually, it's possible to see if the regulator is leaking by taking of the throttle body on top of the plennum, or you might be able to see right through the throttle plate but I would take it off to make sure. take a small flashlight and look inside the plennum on the right side of the engine or passenger side. That's the side the regulator is on. look for any puddles of fuel in the little valleys of the lower intake manifold. For a fuel pressure test make sure you are getting anywhere from 55psi to 65psi...Any spec book will say 50 psi is good enough but trust me, those 5.7's like to run at 60 psi. Also, if you are bleeding down, pressure wise after doing a fuel pressure test ( any more than 5-7psi is not good). Another typical problem is that the injectors which are actually plastic tubes inside the intake plennum have been known to crack which I have seen on a couple occasions. Yet another very typical problem that was mentioned before is the intake man. gasket problem. This problem is because of the fact that Dexcool antifreeze which is GM's extended life red antifreeze is shit...It is corrosive and also has been proven to eat away at the gasket. I've done many of those intake gaskets. To check, spray some carb cleaner around the intake manifold and see if that changes the idle or running characterisics at all. Also good advice was given about the Catalytic convertor from banshee370. Check a spark plug, if they need replacement then it very possible you need a tune up and that said, the possibility of a clogged Cat. exists. It doesn't take long to do so with a prevalent misfire going on. to check, just unbolt the front of the cat from the rest of your exhaust manifolds and down pipes and start her up. if she runs good going down the road then you know your problem. Good luck Edited June 7, 2006 by floyd398 Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.