My 4.3L starts up but immediately thereafter begins to idle rough at about 500 rpm's. Once the engine has run for several minutes, the idle speed will pick up to where it should be. Even after that the engine seems to be sluggish when accelerating.

Anybody with suggestions as to the cause?

The blazer has 93,xxx, I recently installed new plugs, distributor cap, rotor and fuel filter. I'm getting new spark plug wires today but I don't see that changing the problem. Sounds like a sensor though no codes have been flashing lately.

Thanks

 

Go to the auto store and buy Mass Air Flow sensor cleaner. I think I paid $3 for the can at Advanced Auto by my house. Make sure your air filter is clean. Also I reccommend Chevron Techron Injector cleaner 20gallon treatment will clean out your injectors better than anything on the market. Try these out as well as you may want to change your fuel filter as well.

Peace

 

Thanks for the tip, forgot to mention that air filter was changed out with plugs. Is cleaning the MAF sensor difficult? Will this correct hesitation when accelerating?

 

Cleaning out the MAF Sensor isn't hard at all. Just remember how you took it out and make sure your air flow is going in the right direction when you reassemble it.

 

MAF sensor was fairly clean, light film of dust onscreen and same for the sensors and assembly. I gave the unit a spraying then reassembled and started engine. The low rpm and rough idle was still present but seemed as if not as long in duration.

The hesitation while accelerating is still prevelant though. Perhaps an egr valve or O2 sensor is the next steps to take?

Thanks

 

Yes clean the MAF, and I've found that Lucas injector cleaner is great as well. Also for some reason changing the $1.60 PCV valve on these engines makes quite a difference.

 

Thanks for the heads-up on the pcv valve. I should have thought of that.