I have a 1991 integra, when in neutral and only in neutral it revs up and down, sometimes goes almost to 0rpms but then goes back up. Also at times when I start the car(doesn't happen that much) it starts up good but then the RPGs just shoot down almost like the battery is dieing or it's out of gas but if I keep the rims up manually with my foot on the pedal it'll go back to the normal up and down Erving. I'm thinkin tps sensor but I'm not nearly as knowledgable ad some of the people on here. Cel is on but not immediately, takes a bit of driving to turn on. The length in driving for it to turn on always varies, anyways if anybody could diagnose my problem that would be awesome. Yes I searched other threads so please don't give me a hard time about that. Thanks!

 

clean your iac

 

Ditto the above, clean the IACV.

A Google search will get you more then a few DIY vids. 94

 

Thanks, I'll try that and see what happens.

 

check that CEL first it may guide you to the problem. I have had tons of IACV stick and not throw a code.... which is a pain in the rear....

 

Ya it's not iavc or throttle body, both are clean. I would like to see whats causing the cel but no shop will use their readers cus my cars to old. So idk what to do with that. I guess I'm hoping if I fix my idle problem it will delete the cel cus my car runs fine besides the idle. Any other suggestions besides iavc, the cel isn't on right when I start my car, I have to drive it for awhile, sometimes it doesn't even turn on before I get to where I'm driving, how ever long it takes for it to comes off changes every drive.

 

You don't need a "reader" to see the Check Engine light codes. You just need a paper clip.

1) Behind the top of the passenger-side kick panel (ahead of door, under dash) there is a 2-pin gray connector that's not plugged into anything. Jump those pins with the bent-up paper clip.
2) Peel the carpet back in the passenger footwell to expose the gold-colored ECU cover. The cover has a small hole in its surface. Inside that small hole is a red LED.
3) Turn the ignition key to "II" and count the blinks of the Check Engine light.

Caution: When you feed the carpet back in place again, make sure it gets seated all the way, all across. If the carpet isn't fully down, it can foul on one of the the heater cables, making it impossible to move the slider/**** all the way (I forget which, now).

 

I kinda had that problem only it would drop to zero. Just when I sat at a red light it would kinda idle down and back up really quick.
If anyone's ever been in a car that does that its REALLY annoying.
So I found out that it was my spark plug wires. One of the ends of the wires that go onto the distributor ripped all the way off, so I had to put it back on there good enough to get home.
So I changed the wires and the cap and rotor(distributor) and now it stopped all that

 

&my CEL only came on like 20 miles down the road. Turn the car off and it went off and didn't come back on. But was still idling down.

 

Have you checked and cleaned the FITV

 

skipped through the FITV, ill clean that and try what therealtegger said and see what happens, thanks for the help guys.

 

i'm having the same issue i'm all out of ideas on what it is. I think its my fuel pump since i have CEL 43.

 

Changed mine maybe two months ago. Its actually not hard.
My tank is under my back seat. I have a 95 civic coupe.

 

43 could also mean bad oxygen sensor so test it.

 

Yeah I think I might go with a walbro.. I'm sure it won't be hard.