just got finished swapping a tpi 305 into my truck, and now it is annoying me on purpose...

when i crank the truck, it will rev to 2000 then drop down to 500 and stay for 2-3 seconds. then it revs up to 2000 again; repeat

HELP!!

EDIT: 86 tpi 305(MAF) ->s10 5 speed

 

Check your IAC and for vacuum leaks.

 

no vacuum leaks, just re-set the iac and same deal...

 

Is the TPS reading between .55v and .57v at idle? I saw you re-set the IAC but did you make sure the little metal point at the end is clean of any carbon/oil/dirt? You could also try taking the MAF sensor off and cleaning it with MAF cleaner, a dirty MAF will do some funky things. Have you driven it all, does it run ok under load?

 

i have noticed, that when cool, it has a little hesitation off idle, but thats the only other funky thing that its doing right now... the tps is set, i set it per my manual (i dont remember the exact number, I'll have to re-check that) I'll clean the MAF when i get back to the truck, IAC is clean as it can be; BTW, what should stock fuel pressure be set at? I haven't changed injectors, the only thing done to it right now is 2.5 dual exhaust

edit: what's the best way to set idle without a tach? by ear is out of the question, since it has dual turndowns