ok, so i bought this 87 due to someone took good care of it, it has an msd coil pac distributor and wires, k&n filter, custom wheels and all news 5 spd trans and clutch, brand new exhaust...however someone tried to steal it and tore up interior, but that isnt the issue the issue is it passed smog under a year ago with previous owner and now i have to smog it but on a cold start it fires up first crank and runs fine, 30-45 seconds the idle goes up a little. another 30-45 it goes higher and higher to which i rev it and it come down to idle, the truck idles for 30 -45 seconds before it starts to miss fire and wanna die. the engine will rev itself and stay lit but this keeps going on and on and on, if i stop at a light it feels the idle is too low and it will occasionally die but will fire right back up with the first crank. im totally lost on what is causing it cause im getting 24 mpg on average and the timing reads 20 degrees on the balancer. ive put in a new temp sensor and iac neither of which did anything unless i somehow got a bad iac from duralast. i bought this truck for work and play but im at my end with this thing, If it dont pass smog and run right i dont want it does anyone have a clue to what might be my issue?

 

Check the butterfly shaft on the throttle body for any up/down , side to side play.
Also check the throttle plates where they contact the bore to see if they have worn a groove in it . It may be leaking vacuum in these areas.

 

ok, i checked for regular vaccuum leaks with throttle body cleaner buy didnt notice any of those issues ill take a look and let you know

 

checked and cant find any leaks around throttle, however the idle screw isnt touching the throttle cable, i know your not supposed to adjust them on fuel injected cars but could this one be turned in without killing my smog?

 

Did you ever figure it out mines doing the same thing.THANX!

 

I replaced it and it works GREAT now,it's in the intake manifold.Hope this helps.