My 4.3... continues to start hard...and run rough...I recently put a bottle of GM Injector Cleaner...$20.11 in the gas for a tank of fuel...
This seemed to clear the rough idle some...but not enough...I have removed replaced the erg valve twice...and the next I am to do is have a diagnostic mech. in my area look further for a fuel pressure problem or internal fuel line leaks...any other ideas would be welcomed...Should I try another bottle $21. of the Strong GM injector cleaner or go to the mechanic...do not pass go...

Have You Tryed Seafoam Cleaner?

Also, double checkand make sure it was the right "dose" of fuel injextor cleaner, I know the chevron with techron comes in at least 2 different ammouts treatement for a 12 gallon tank and treatment for a 20 gallon tank.
Your posting in the blazer forums so I assume you have a blazer and they have 20 gallon tanks. Putting a 12 gallon treatment in a 20 gallon tank will be dilluted it alot and it may not have much of a lasting affect.
I would say check your spark plugs and replace them if nessecary also, my blazer was also running rough and getting bad mileage until I got new plugs.

Thanks for the info. guys...I have tried seafoam...2 cans to a tank of gas...no help...the plugs were just changed...It is a 1993 GMC Jimmy...but I see now that I must dig into the fuel delivery/pressure regulator...poppets...It is easier to just talk about the problem here...and also easier on the pocket...I see I need to take it in... :o)