93 FD Rx-7 rough idle on cold start (with video)
 

Hey guys hoping to get this problem diagnosed and i thought the best way to do this was to make a video of exactly the problem instead of trying to write it out, but i will give you guys a quick crash course as to the problem anyways. When starting my car from a cold start my idle will jump right around the 2 grand mark for a good 3-4 minutes but will slowly go away into a strong steady idle (as seen in video). I'm hoping my very knowledgeable rx7 community can help me find and solve the problem or just tell me it's nothing major and to leave it.

It's worth noting my car is completely stock at this time however i just recently purchased and new intake (pettit) and AST as well as some maintenance things (fuel filter all that jazz). I thank you guys for your time and i apologize for the mediocre quality of the video and my lack of the English language at the end of the video hahaha what i was trying to say was "leave a comment in the comment box":lol:

Video link: http://www.youtube.com/watch?v=giuoY...ature=youtu.be

Thanks again guys :nod:

The loping idle makes me think of a vacuum leak. I'd expect it to improve as it warms up, but not sure why it goes away.
You might try cleaning the Idle Air Control Valve (IACV..or sometimes just referred to as the IAC). They don't often go bad, but apparently get dirty from the PVC emptying into the manifold nearby. SEE FSM
I cleaned mine once..just because. Used a little brake parts cleaner and got a surprising amount of black soot/gunk out. It's on the aft side of the upper intake manifold...iirc two 10 mm nuts and a single connector. Again, not sure that will solve it, but it won't cost much to try. Maybe someone else will chime in with a better idea.

Very nice FD. Could be a vacuum leak, or IAC like Sgtblue suggest, or a bad solenoid. Does it still have the stock vacuum hoses? If so you should go with a silicone hoses, look a www.hosetechniques.com for a kit. Or you could go with viton hoses, a little more expensive but it will last a goon's age. Not sure where you could get it though.

Because cleaning the IAC would be easier, I would try that first.

Is the boost pattern normal? 10-8-10?

I'm having the same problem. Let me know how you make out.

My 88 was doing that until today. I changed the throttle position sensor (TPS) and it runs great. I believe you are having the same issue since mine ran for about 5 minutes the same way until it warmed up. When warm it idled fine. Guarantee this will do it for you. Good luck and please let me know how the project goes. Cheers!

Also, look on ebay for the sensor. It saved me about $175 on the price.

Thanks for all your guys inputs i'm literally going to try everything suggested so far.

Jeff- yes it still has the stock hoses i plan on changing those very soon so thank you for the link and also my boost pattern is normal running a 10-8-10

You can check the TPS with a volt meter, here are some links on what to do.
http://www.fd3s.net/tps_adjustment.html
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fixed-my-idle-problems-backfiring-bucking-more-170731/

Good luck!

Oster-
Did the TPS solve your problem? Having the same issue.

OsterFD3S hasn't been on the forum in about a year.