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I have 1993 Civic 1.5 liter automatic transmission with 103k miles. When I start it in the morning it takes 5 minutes for the RPMS to drop down before I can put it in drive or reverse. My question is,what controls how long the engine is on fast idle? if I put it in drive or reverse when it is idling fast, the engine stumbles and almost dies. After its warm, it runs perfect.

Thanks!

 
Rep Power: 518

Yes it should idle faster while the engine is cold.
The colder it is, the faster the RPM will be.
Idle RPM should slowly come down as the engine warms up.

How fast might be questionable, is yours idling too fast for a given temperature? You may want to compare to an identical car or ask the owner about it.


If coolant level is low, it may not come down correctly.
If the engine can't warm up correctly the idle may not come down correctly.
If the IAC or FITV is bad or stuck, idle may not come down correctly.

If it just runs like poop when you drop it into gear you might want to check basic tune up items. Got any codes?

 
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Thanks for the response. I understand the engine should run faster when cold, but I think 5 minutes is too long. Normal cars take about 30 seconds and drop down to 600-700 RPM. Coolant level is fine. How do I run codes on a 1993 without OBDII? I might try cleaning the FITV. thanks!

 
Rep Power: 518

Jumper the SCS connector, read basic flash codes

 
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A 1993 Civic will not drop down to 600-700 RPM in a minute. Never has, never will, unless you live in the tropics. However, dropping it into Drive or Reverse right after starting it while it's at high idle should not significantly effect the idle. If it does you have a problem. I would start by ensuring you have no air in the coolant, then make sure you don't have a vacuum leak, then I would check and clean the IACV or adjust the FIV. Or watch this




Do you have a CEL light?