Recently picked up a 94 blazer silverado with the350 engine. The truck idles extremely low, especially while in gear. Where can I adjust the idle speed? I'm not real familiar with the 350, all my other cars have had a screw near the throttle body. Thanks!

 

I just put a 94 350 in my old truck. Between the Chiltons manual and the Chevy factory service manuals I think it states the idle is set by the computer. Mine idles at about 600 in park and 550 in gear

 

I think you can "tune" it to a higher idle. Maybe a chip?

Honestly I think you have a vacuum issue somewhere or maybe you just need to clean your TB. I bet it is something simple.

Things to look for and try:

1. Clean the TB
2. Replace the PCV if you haven't already.
3. Run Sea Foam through with a tank of gas.
4. Check plug condition and gap.
5. Check distributor cap and rotor for moisture, debris, wear.
6. If it has a MAF sensor, clean it.
7. Replace Air Filter if it needs it.
8. Check for vacuum leaks, maybe clean system with Sea Foam (see below)


Sea Form the Vacuum System:
1. Aim truck exhaust away from your house and any small children.
2. Pull vacuum line from a central location on engine. Make sure it draws air into the tube. Brake booster would work.
3. Start truck.
4. SLOWLY drip Sea Foam into vacuum line using a funnel or something like that.
5. Do this for 10-15 minutes if you can, rev the engine periodically. If it stalls out, just restart and continue.
6. You will notice the truck will run a little quieter and smoother after a day or so of driving.
7. NOTE: Exhaust fumes will be highly toxic while doing this!!!