Rough Idle - 2002 S10 Crew Cab


New member
May 8, 2013
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I'm a new member...this Forum is the closest I could find to S10 Pickup's....if there is an S10 Forum please let me know and I'll redirect my question!

Vehicle is a 2002 S10 Crew Cab "W" engine (no EGR), AT, 4WD with 108,000 miles on it. The engine starts great in all weather. It idles a little faster when cold then slowly decreases to what appears to be the correct warm idle speed. It sounds great at all speeds....pulls well from a stop light - no hesitation/stumbling. There are no engine management lights flashing on the dash.

The motor idles at 550-600 rpm in drive and is rough - not rough enough to stall the motor but rough nevertheless. I changed the plugs and replaced the air filter. The fuel filter was replaced about 10,000 miles ago. I replaced one split/cracked vacuum hose right around the top of the brake change in the idle. I didn't follow that line inside the truck (under the dash) to validate it's integrity but heat and the elements shouldn't have affected those hoses???

Are there any other components or perhaps another vacuum line I can't see that might be causing this?

Thanks for whatever help you can provide.