i know this has a post somewhere in this forum, however i feel my situation is alittle different than most.. my question is what would a cause an engine tohave idle surge, my truck only does this when idleing in park..as soon as you drop it in any gear the idle smooths right out.....it also has a tendency to have a high idle, its strange cause if you tap the accelerator pedal it will drop back down to a normal idle.. and after normal driving the idle goes back up in drive, you tap the pedal and it drops again i have greased all the linkage and that seems to all be ok .basic tune up parts are all new ( cap , rotor , plugs , wires & pcv valve.)
tps and O2 where replaced about a year ago
any ideas guys
thanks

 

clean the throttle body with teflon safe throttle body cleaner like deep creep from napa. also clean the MAF sensor with clear rubbing alcohol. and while your at it clean the IAC it is located on the trottle body be careful when you clean the IAC they break easy.

 

WHAT CAN I CLEAN THE IAC VALVE WITH ?

 

What is the voltage from the tps at idle? If it is above 1V then it won't idle right. There is no maf sensor on an '87, so don't go crazy looking for it - it isn't there. Jack01, how would you break an IAC? I'd clean it with some throttle body cleaner and a toothbrush to get out as much carbon as you can.

 

you can clean it with the same cleaner for the throttle body and the IAC (make sure that it is safe for telfon coatings.) I just cleaned my throttle body today and man was it dirty I used deep creep from napa and it ate thru most of the deposits. and my truck seemed to have more power after I put it back together.


as for breaking the IAC I have seen people remove them an drop them and that breaks them.

 

I gotcha, dropping it would definitely break it. I thought you meant while handling it, but I understand now.

 

i think i may have screwed up, cause i remember clean the throttle body, the iac valve and the whole outside of the throttle body with regular carb cleaner, come to thinkof it it started running crappy after that, damn i wonder it that stuff got in some of sensors.....im going check the tps with a ohmn meter and post back thanks for all the replies guys

 

the truck in my sig is having the same prob guys. it wouldn't surprise me if my throttle body is nasty like you mentioned. can someone describe what it looks like and tell me where to find it?