I have a 1988 2.8L Chevy S10 Blazer with a high idle problem. Its has 234,000 miles on it. Its all tuned up replaced IAC. It was up to 1050 RPM but have gotten down to 800. Can anyone show me a picture of where exactly I drill to get to the idle screw to adjust it. And after I adjust it I imagine I have to reset the TPS. Would I also need to reset the timing?First thing id do is stop using aol lol. God i remember waiting for that damn disc to come in the mail for the free usage.
Second you only touch the timing if you some how jumped a tooth or you accidentally spun your distributor and threw the timing out of wack.
the only drilling i remember reading was the bolts on the tps were pressed in bolts with smooth flat head. mine were torques bit i think.
third if you cleaned your IACvalve did you follow the cleaning instructions to the "T" cause some ppl were messing then up using abrassive agents. also when you remove the IAC the plunger will get miss adjusted and only way to learn its position is to have a tps sensor properly installed. you'll need an ohms meter and a chilton's manual. top of my head i dont remember specs. Adjusting idle set screw is simple no drilling needing i dont think. but honestly i backed mine all the way out till so that idle adjustment would hit the mount or whatever the screw is mounted through then tightened it so that it just lifted the throttle back up just enough to say air can pass.
Mine was or is still i should say, the twin port fuel injected throttle body. And with my high idle issues it could have been:
*simple idle adjustment
*dirty IAC Valve
*dirty EGR or old vacuum hose dry up. they are plastic and crack and i remember so many damn vacuum hoses to check
*coolant temp sensor(not coolant temp sending sensor-this one is for the gauge feed and i think they are pretty close to each other
Bad sadly my first high idle i checked all the above and my issue was someone had pulled the cable that whys off for the cruise control plunger unit which has a piece of flat metal with holes in it that you can change it to take the slack out the line so the throttle never dropped all the way down. one of those things youd never think was the issue
i love my 92 gmc sonoma and the 2.8l 5speed was pretty fun to drive. But mines been parked cause i put a new water pump in and was broke and live in tx so said f*ck it waters free and it never freezes. But two years ago tx froze for a whole week state wide and froze the motor and pushed out freeze plugs blew the hoses and i can only guess but messed up the intake gasket cause after it should be full after adding coolant it keeps taking it till it comes out the valve cover oil add port. But fires right up and doesnt have any misses. actually bout to go out and start taring it down. which is the reason im on a 20+ yr old thread waisting time responding to ppl who are either dead by now or in prison. Im just procrastinating. But if you still got troubles hope this helps