Why is my Chevy truck bucking at idle?
During idle it would sound as if it were about to shut off but it wouldn’t. Rough idle and hesitation sounded like a vacuum problem, so I checked the TBI. The EGR valve was faulty so I replaced it. That fixed the rough idle and it drove fine for a day or two. But then yesterday and today, my truck began to buck pretty hard.
What’s the idle RPM on a Silverado Silverado?
Re: high idle PLEASE HELP!!! When i pull the vac line from the booster the idle rpm stays at the 1200 I had been idling for 2 yrs. It only runs rougher but maintains 1200. When I pull the same line from the back side of the intake she revs really high. Enough to scare you so I plugged it back in really fast.
Is there an intake manifold leak at high idle?
You may have an intake manifold leak on the bottom side of the engine at the lifter galley (I base this assumption by the fact that when you spray eather into the valve cover it changes the engine speed.) Re: high idle PLEASE HELP!!! You probably have a leak like aste25 mentioned.
What causes a car to have a high idle?
It’s really hard to say, but I will say that those engines are prone to intake gaskets leaking. A vacuum leak can cause a high idle, if it is a small enough one.
What should the idle rate be on a 1997 GMC Truck?
Underdog, I don’t know the 1997 5.7, but 1000rpm sounds like a high idle, not where it should “bottom out”. A V8 should idle at 500rpm. GoNDown, did you recently disconnect your battery? After I left mine dead in the yard for a while and didn’t charge it, when I started it up it ran like you describe for a few days and then it was fine.
During idle it would sound as if it were about to shut off but it wouldn’t. Rough idle and hesitation sounded like a vacuum problem, so I checked the TBI. The EGR valve was faulty so I replaced it. That fixed the rough idle and it drove fine for a day or two. But then yesterday and today, my truck began to buck pretty hard.
You may have an intake manifold leak on the bottom side of the engine at the lifter galley (I base this assumption by the fact that when you spray eather into the valve cover it changes the engine speed.) Re: high idle PLEASE HELP!!! You probably have a leak like aste25 mentioned.
Re: high idle PLEASE HELP!!! When i pull the vac line from the booster the idle rpm stays at the 1200 I had been idling for 2 yrs. It only runs rougher but maintains 1200. When I pull the same line from the back side of the intake she revs really high. Enough to scare you so I plugged it back in really fast.