Idle problems i have a 94 blazer that idles rough but when i drive it it then straigthens up can u help me with this I have the same issue on a 95. Where is the egr valve and is it avaiable at NAPA or autozone etc? Thanks

when was the last tune up done on it? have you checked the spark plugs and firing order to make sure it is correct?

I can be problem with IAC valve or motor,or there can be vacuum leak issue it its dirty Idle control valve or problem with dirt build up in throttle body.Click this link below and follow step by step troubleshooting:-----http://whatisbyme.blogspot.in/2012/05/high-idle-on-chevy-blazer.html
---------------this should help.Thanks.

When you changed the egr valve did you clean out the carbon build up inside the intake? if not that could be the problem, if you did, than a peace of the carbon got stuck in the valve, either way your local auto parts store sells a screaned gasget for the egr valve to prevent peaces of carbon from the intake geating into the egr valve, same exact thing happend to me on my 95 blazer.

I would get a good tuneup!! plugs, wires, airfilter,

CHECK FOR A LEAKING INTAKE MANIFOLD GASKET, USE A CAN OF CARB SPRAY AND SPRAY AROUND THE TOP OF THE ENGINE, IF U HIT ON A LEAK U WILL HEAR THE ENG CHANGE TONE AND IDLE RPM.

o2 sensors often cause a rough idle at stand still. Previously my xj8 had crank case ventilation (pvc valve essentially) issues that caused the check engine w/ restricted performance. I noticed a severe drop in gas mileage as well. Jaguar dealer fixed my problems in a few hours and it was surprisingly cheap. Its worth taking it to advanced or auto zone to see what the computer says. Then decide if you want to shell out for a dealer fix or if you can tackle it yourself. BTW, just to justify myself this is my third jaguar. I have a '94 xj6 with a chevy 350 inside it, previously owned a 95 XJ6 and currently have the xj8. They are wonderful cars if you can put up with their rough times.

if it is a vortec 4.3l they were real common for egr valve problems. you can remove the egr check for carbon stuck in the plunger. after cleaning reinstall with a new gasket. New gaskets with a screen are available to keep this problem from happening again the standard part number is VG57. When carbon gets stuck in the egr valve it causes a vaccum leak and rough idle. please rate this if it helps

Could be vacuum leak or bad ignition wire(s).

I had a similar problem on my "93 Ford probe. The engine idled pretty rough with shakes, Turned out to be a head gasket leaking engine coolant into the cylinder during low rpm's. At fast rpm's it was fine becuase the internal cylinder pressure was greater than the hot coolant pressure & would prevent the coolant from leaking in.

A friend has the same problem with his "94 Blazer 4.3 L, throttle body injection, manual tranny. He hasn't fixed it yet, It started a few weeks ago & is getting worse. His gets a fast idle with hiccups which causes the engine shake. He already checked the EGR valve. He also has a severe exhaust problem, Not oilly but very gray & terrible smelly, but only when the fast idle problem happens. THis fast idle hiccup problem starts when the engine is warmed up.

check your Throttle Positioning sensor that should fix your rough idle the TPS controls the breather on the front of the engine its affixed to the right hand side of the throttle body just infront of the spyder on the V6 Vortec 4.3L Models

I have a 1994 Cadillac Eldorado and every time i start it the car has rough Idle and the Idle fluctuate's. I also can feel it in the gas pedal when the car is doing this I tried replacing the throttle body sensor but it still does it I also was told it was the Idle error sensor. So instead of spending the unecessary money again I thought I would go online and see if anyone could help me with this problem.