Mechanics

CAR STALLS OFTEN WHEN I STEP ON GAS

1998 GMC Jimmy • 6 cylinder Automatic • 125,708 miles

My car stalls often when I step on gas. At takes about 3 or 4 cranks to start. Is this a sign that my fuel pump is gone? Thanks.
Avatar
Roycar71
July 20, 2012.



Scan for codes an dcheck fuel pressure first. Clean throttle plate with choke cleaner on both sides. As well as iac hole if it has one. Fuel pressure shold be 60-66 psi. If below that it may be a pumpor filter clogged.


Hmac300
Jul 20, 2012.
I am a little vague on somethings. The throttle plate is located in the air filter assembly right? Where would iac hole? Thanks.


Tiny
Roycar71
Jul 21, 2012.
Go to tune up on the site here it will show you where the throttle plate is. But it is just above the intake manifold. The iac hole is a an oblong hole ontp if you have one.


Hmac300
Jul 21, 2012.
Ok, found it already and took it off top of intake manifold. Real easy to get to. I cleaned plate, inside throttle body by moving spring mechanism back in forth and got alot tar gummy stuff off. I used throttle body cleaner from auto zone. Put everything back together. I drove to take someone home and did not have any problems. Gmc jimmy ran smooth even though I noticed gas pedal went down easy and there felt like a lose of power, but ran fine nonetheless. Today, being sunday I got up early and change my fuel filter and gassed up. There was few times I had to crank truck more than once to start and stalled/sput when I stepped on gas for a few secs and then it would go hard. I thinking to just go ahead buy fuel pump and replace it. If it was a relay. Wouldn't check engine light come on and fuel pump will not work, thus car would not start, right?


Tiny
Roycar71
Jul 23, 2012.
Actually with a fuel pum check engine light will not come on unless it sets a code of a lean condition. So make sure you check fuel pressure first before you change it, it may all be for naught.


Hmac300
Jul 23, 2012.
Yep, I just order a fuel injector pressure gauge to test my psi on fuel test port. I will post results.


Tiny
Roycar71
Jul 23, 2012.
Most auot parts stores have them for rent where it won't cost you anything if you birng it back from a deposit.


Hmac300
Jul 23, 2012.
Yes, I know. Over here I get round around alot so I order one and got today. I hook it with know problems. I got 60 psi with engine running and when I turned off engine it went to 0. I saw some videos that said "your bleed down should not go to low". If so, maybe I am missing a o-ring when I change the fuel filter or something. Plus recently, when starting up it takes a few extra cranks to start and when you step on gas it feel like it is stalling and there appears to be knock sound coming from rear underneath car. Then it take off fast. Thanks.


Tiny
Roycar71
Jul 26, 2012.
That can also be the fuel pressure regulator bad.


Hmac300
Jul 26, 2012.
Could I test the fuel regulator or just replace it. Is it easy to replace?


Tiny
Roycar71
Jul 26, 2012.
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