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Rough Idle and engine sputtering

Thayes54
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Thayes54 New Member

Thayes54

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I have a 5.7L TBI engine in my 94 GMC C1500. The truck is running really terrible. It’s sucking in ALOT of air through the intake without pressing the pedal also it has a really rough idle and when accelerating it sputters and kind of hesitates. It started with the O2 sensor code. I replaced it. Code went away then code 32 popped up. I replaced the EGR VALVE and the Solenoid. Still was having issues. I just replaced the TPS sensor, spark plugs, MAP sensor and still having the same issue. 
 

Could it be the IAC Valve messing up or something else? 

Thayes54 New Member

Thayes54

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5 minutes ago, riverbanks said:

Have you checked all vacuum lines for leaks?and how does the spray pattern look on injectors?

I’ve visually checked the the vacuum lines I don’t see any tears or disconnection of any lines. And not sure on the spray pattern. I did run a fuel injection cleaner and that seemed to help it a little bit but not much of a difference.

riverbanks Senior Enthusiast

riverbanks

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You could spray some carb cleaner on all vacuum connections all the way to the booster,listen for idle change,and what about p.c.v?stuck open?as far as the cleaner?how dirty was it under the egr? thinking, carbon on backside of intake valves,think another round of cleaner?

Thayes54 New Member

Thayes54

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12 minutes ago, riverbanks said:

You could spray some carb cleaner on all vacuum connections all the way to the booster,listen for idle change,and what about p.c.v?stuck open?as far as the cleaner?how dirty was it under the egr? thinking, carbon on backside of intake valves,think another round of cleaner?

The egr was replaced last year when the last one was stuck open. When I replaced it again recently the ports was mildly dirty not to bad. Should I remove it and spray some cleaner in the ports? And definitely haven’t checked with the PCV. I went ahead and ordered a new one (saying it’s only $4 so why not) 

riverbanks Senior Enthusiast

riverbanks

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I wouldn't clean under egr with manifold on, maybe cause a issue,you can't correct without disassemble,so new pcv,can't hurt, possible vacuum leak,spray test on vacuum lines,and with a flashlight,watch injectors for a nice cone spray pattern

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