Repost (Surging idle and running lean)

[mclark]

Hey guys just an update from the last posting, after checking and replacing all that I knew to do my final option was to replace to the computer . Computer was ordered, arrived and installed and problem resolved. Surging idle and running lean problem gone . Been driving the Sho since computer swap, guys it feels great to have the Sho running like it should. Once again thanks for all the responses .

 

[luigisho]

good news. If you can find the original thread post this as a resolution for the next person trying to search

 

[Irish Pride]

Glad to hear that you got it fixed. I just fixed my surging idle tonight too. I wish mine was as single as a PCM swap though. I've been dealing with mine off and on for the last month. My EVTM came in very handy again.

-Chad

 

[luigisho]

Well dang Chad don't just leave it out there. What did you track down?

 

[Irish Pride]

Well dang Chad don't just leave it out there. What did you track down?

For me, it ended up being several things all combined to give me an uncontrollable idle. This project car sat for 13 years before I got it and another 2 years before I started messing with it. First it was a shorted BARO sensor causing the TPS to throw a code(121). Then it ended up being a sticky IAC(411). Finally after getting those two things sorted out the final issue was this car has a modified throttle body on it, 69mm, and someone had previously adjusted the set screw so that the throttle plate was completely closing and sealing off any air from getting in and the IAC couldn't keep up. Last night I was able up dial in the set screw and for the first time this car idles great and no longer surges or dips. Now I just need to get it on a Dyno and fine tune it.

-Chad

 

[luigisho]

Holy crap. Tip my hat to you being that persistent. I probably would have killed mine by fire and tire iron before I tracked all that down.