Hey guys, ive got a 94 S10 Blazer with a 4.3 w vin code, and i had to replace lifters, push rods, injector, fuel line kit, TPS sensor, and manifold pressure sensor. now after getting it back together cleaning everything, and installing new gaskets, i start it and it idles around about 2500 rpma, then when i put it in gear it kicks really hard, and idles fine. also when i let go of the brake when in gear the truck stars accelerating by itself to about 20 MPH any suggestions?

 

Check for a vacuum leak. Spray carb cleaner around the areas that seal and also vacuum lines. If it makes a difference in idle then you'll have found your leak.

Edit, Also, you say it kicks in gear hard and accalerates to 20MPH then its not idling in gear fine, its going in gear and kicking down the rpm's, I am sure your applying more brake pressure as if you were power braking it before you tore it down.

 

does the engine ever idle down?

 

good idea, is the Idle Air Control Valve working properly?

 

i did spray carb cleaner around and found one spot, i guess the guy who did my timing loosened a plenum bolt the idle did go down a little im going to check the idle control motor again, i did replace it a while back because someone smashed it with hammer when i bought the truck