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Hey! Im new to this forum so forgive me if this post is on wrong section. But here comes my problem that started several days ago as weather is getting colder here in Finland.
When i cold start my car in morning idle is jumping up and down almost like its gonna die there for a moment then it does some corrections to idle speed and it jumps pretty high, sounds like its running like 1700 - 2000 rpm at least. Well then i give it a time to get warm little bit but idle stays high so putting it in drive is pretty jumpy experience. Once it warms up more idle comes down. Could it be iac going bad or what, i have cleaned TB and IAC + its passages in summer while i did my intake gasket replacement. My car didnt do this last winter when i drove it couple times at -10 to -5 celsius. Also i already tried to find vacuum leaks with break cleaner but found none. My idle has also always fluctuated small amount when warm too but never have found reason to it. Next time i start it i will try to remember to take a video of it, because that of course may explain situation 100x better than i can with my words.

Thanks for any help upfront!
 

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Welcome to the forum.

First thing to do is to get a fuel pressure tester and hook it to schrader valve on fuel rail. Turn key on & let fuel pump prime the fuel rail. You should have around 43 psi of fuel pressure. remove rubber vacuum hose from fuel pressure regulator. Block hose so vacuum doesn't draw air in. Start engine and let idle. Pressure should be in mid 30's psi to about 40 psi.

Next read codes. Fleetwood should be able to read codes without a scanner. Consult owners manual on procedure, as I don't know it. GM website will usually let you download your car's owner manual for free. If you don't have it.

I would buy an obd 1 scanner. One that can do running sensor scans. The sensor data received from a running sensor scan would help to point you in the right direction to fix your problem.
 
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