I have just replaced the spark plugs on my 98^4.3 lt Chevy Blazer but have not replace the rotor. The idle trouble continues at low speed but dissapears from 20 to 65 miles. I have recently change oil, fuel pump and valves cleaned. Could the rotor be the reason for idle trouble or some sensor perhaps must be replaced ?

 

If you do not know how old the wires, cap, & rotor are, I would advise you replace them as part of a typical tune up.

You may also want to remove the EGR valve and throttle body and give them a good, thorough cleaning while you are under the hood. You will need to purchase a new gasket for the EGR valve and when you do, get the one with the integrated screen that will help diminish the possibility of the valve clogging again in the future.

 

Thank you for your quick answer, I will follow your advises

 

I had huge issues until i replace the cap and rotor. Idle issues and trans shift issues. money well spent.