I have a 1991 RX-7 that I'm having idle problems with. After warm up idle bounces up and down 300 RPMs around 1000 to 1300. When the engine gets to its normal hot running temp sometimes it idles fine, around 800 to 900 RPMs and other times the idle bounce is back. If I blip the throttle it might settle down to 800 rpm. If I force the throttle body closed by hand it will settle down. Before I mess with it and screw it up I need ideas on what to look for that might be causing this. I figure someone out there might might be able to help me. The engine is completely stock.
j_tso
SuperDork
12/18/24 8:45 a.m.
it's been a really long time since I touched the FC RX-7 EFI, but have you checked your throttle position sensor adjustment?
How-to link
Snrub
Dork
12/18/24 8:55 a.m.
It's been a while since I've had an FC, but there's an idle adjust screw (I think) at the air control valve. I'm pretty sure something like that resolved a similar issue I had.
Been a while for me, too. Here's what I remember:
If your TPS is out of adjustment or failing, it might cause some weird things to happen. Check that, clean the throttle body, clean the plunger in the AFM if that's sticky, then see if the idle adjust screw needs adjusting.
There are multiple places you can find the factory service manual for FCs.
In reply to j_tso :
Thanks. I have checked the throttle sensors but will recheck them again. Forgot to put this in my original post that this is a non turbo car.
