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-   -   New owner with idle issues (https://www.rx7club.com/new-member-rx-7-technical-256/new-owner-idle-issues-1172327/)

StarkTruss26! Jan 21, 2026 03:00 PM

New owner with idle issues
 
I wanted one for a while and took someone up on an offer even though its having idle issues. (1989 Rx7 fc s5 n/a vert) I would love some help with Diag. When AWS is activated it idles fine, When the car is at 1500-2000 (wax temp?) it still idles fine but when it is supposed to drop below 1000 it just tanks rpm and dies every time. I am going to inspect BAC for proper operation but I am not convinced on what the issue could be. It runs perfectly when you are on the throttle it just has issues with idling. I dont want to say vacuum issues yet because im still in denial from the past 4 vehicles that ive owned having a vacuum issue in one way or another but I would love some advise on what to check first. This is also bone stock, emissions and everything.

Jeff76 Jan 21, 2026 04:35 PM

9 times of 10 with these cars it is a vacuum issue, sorry. :lol:

Start with the TPS set procedure first. I had my car for years with idle issues. The proper idle set procedure worked, I did mine with the two light method. Then the 1 volt method later at the ECU, that seemed to work a little better.

TPS

My idle speed still drops occasionally, I will have my ECU recapped and see what happens.

StarkTruss26! Jan 21, 2026 04:51 PM


Originally Posted by Jeff76 (Post 12647414)
9 times of 10 with these cars it is a vacuum issue, sorry. :lol:

Start with the TPS set procedure first. I had my car for years with idle issues. The proper idle set procedure worked, I did mine with the two light method. Then the 1 volt method later at the ECU, that seemed to work a little better.

TPS

My idle speed still drops occasionally, I will have my ECU recapped and see what happens.


I have check engine codes 11 and 17 which is if im not mistaken intake air temp and oxygen sensor if that helps

Jeff76 Jan 21, 2026 05:07 PM

Yep, that'll do it. 11 for sure, not sure about 17. The O2 in S4's don't do much, maybe they do in S5's

https://www.rx7club.com/2nd-generati...des-s5-176590/


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