Idle speed?

[Fiero91]

I have an 84 base model Fiero, and it's in the process of being restored, it starts and runs great, but it idles at around 2000-2100RPM is that too fast? if so, how would I correct it?

 

[Fiero91]

Also, the car is getting REALLY bad fuel economy, like 10MPG, since its a 4-cyl manual, that seems really, really low. Any help would be MUCH appreciated!

 

[Oreif]

Normal idle should be 850 to 900 rpm in neutral.
You most likely have a vacuum leak, bad IAC, or bad/dirty throttlebody.

Idling at 2000 + whatever that is bad and causing it is killing your gas milage.
Typically you should be in the 20mpg range.

 

[Fiero91]

Developed another problem, when I start it, it runs, idles at 2000, and after about 5 seconds or so, the engine speeds up to about 2400 then goes back to 2000 all in the span of about 4 seconds, it repeats this over and over, going from 2000 to about 2400 then back to 2000 when idling, any ideas what could cause that?

P.S. - I love this car but man it's so annoying sometimes!

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[Oreif]

As I said before most likely a vacuum leak. The cycling of 2000 to 2400 is the computer trying unsuccessfully to compensate.

 

[Fiero91]

Probably a stupid question but is there an easy way to check the vacuum lines? like can the non-sensor related ones like maybe cruise control be unplugged at the source and the hole plugged up?

 

[Fiero91]

An easier way than spraying them with a can of carb cleaner I mean