So yeah, I am extremely happy to report that after 6 DAYS I finally fixed the idle surge on my car. Why 6 days? Well, here is the full, painfull experience. It's long, but I am somewhat intoxicated after some celebration.

I performed a mini-me swap and converted a '92 DX hatch from automatic to manual several weeks ago. Neither was that difficult, but it did take me some time, as I worked on the car alone, learning as I went. Once completed, the car had an absolutely wicked idle surge; it would initially jump to 4k rpm and then bounce from 800 to 1800 about once a second once the car warmed up a little. Once I dug into the car, nearly every issue I checked made no difference.

-checked all vacuum hose routing and re-tightened all of the manifold bolts. Everything was cherry.
-I swapped 3 different IACVs onto the car, including a b18b IACV. No dice.
-checked the voltages on MAP, IACV, TPS. All within acceptable limits.
-swapped three entirely different throttle bodies, including a MAP-on-the-firewall style setup. No dice.
-checked with the carb cleaner spray down. While I emptied a bottle, got really high from the fumes, and cleaned up my motor, I had no vacuum leaks.
-cleaned out a IACV and re-tightened a FITV. No change.
-changed the PCV valve. There was an immediate change in peak idle, but the surge continued.

At this ponit, I was about ready to cry. Then, for ***** and giggles, I took the TB off again, and upon closer inspection, noticed that the new TB gasket I put on with the swap was overlapping one of the holes for the FITV. With a razor, I cleaned it up, re-installed, and started the car. This time, there was an instant improvement, although the idle was still shaky. I called a friend, who brought over a different p28 ECU and what do you know...idle fixed, problem solved, kick me in the *****. My ECU was dead, and apparently causing the MAP, TPS, or IACV to act kinda funky.

I dropped in my old dx ECU, which works, but I am now missing VTEC

So the moral of the story?? Idle surge sucks. The end.

*on a side note....I am now in need of a virgin P28....drop me a PM if you gots.

 

I like the way you accent that - "6 DAYS"

My probe had a surging idle for like a year.

I simply never gave a expletive.

As for a stock P28. Look in the "FS" forum and/or post a "WTB" ad.