Rough idle

FDLECUYER

MEMBER
GMC C1500

I have a 2001 GMC c1500 with a 4.3L. The engine run very rough on idle or not at all. I don't any sensor code but I do have misfire on all cylinder and it run rich on both bank. I change the the plugs, wires, cap and rotor ran fine for a month the problem came back, the plugs were very wet. Theres lot a gas in the oil. I change the EGR, looked at the IAC seem to work fine. The CTS and the MAP are OK. I don't know where is the fuel pressure regulator so I haven't look at it. The catalityc converters looks OK, but I don't know how much backpressure I should have. I did an injector balance test looks OK but my gauge was leaking so I need to do it again. Thanks!

4 Replies

BOOMER2782

MECHANIC
22 POSTS

I have a 99 silverado 5.3 liter. My fuel pressure regulator is on the center of the driver side fuel rail, above the injectors. You might want to look on your fuel rail for it.

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Tuesday, February 14th, 2006 AT 2:25 PM

KENVCR

MEMBER
105 POSTS

If your 4.3l has a throttle body intake it will be located at the back. It is a sealed unit. You must replace it. Make sure you get the gaskets that will be required when you take it apart.
Please post a reply if you figure this out for future reference.

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Thursday, February 16th, 2006 AT 12:58 AM

FDLECUYER

MEMBER
9 POSTS

I took the intake apart, replaced the fuel regulator and cleaned the excess fuel inside. Putted every back together, removed all the spark plugs cleaned them and turn the engine without them, then installed them and starded on the first try. I had to replaced the idle air control it couldn't stay idle from time to time but since then everything work fine.

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Tuesday, April 11th, 2006 AT 7:48 PM

KENVCR

MEMBER
105 POSTS

Thanks for the reply. I am currently experiencing a similar problem with a 4.3 engine. It has us baffled for a couple of days now. All our engine scoping and analyzing has come up blank. We did not even think about the IAC. Thanks to your reply it will be the first thing re & re'd tommorrow.
Kenvcr.

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Thursday, April 13th, 2006 AT 2:14 AM