My civic with a d16 can't keep its rpm's in one place. they bounce from 1k to 1500 at idle. when i unplug the maf or iacv sensor then it stays steddy at 800rpm. any thoughts would be great.

 

What year/model? How many miles? Do some recent maintenance or modification?

 

It's a 4 door 95 civic EX, the motor was put in not 18 months ago. it ran then stopped starting up. i moved and it sat for a year before i could get back to work on it. just got it running 2 1/2 weeks ago. i'm going to bleed the cooling system and try to adjust the throtle. any thoughts?

 

Is the CEL ON?

Also try cleaning both the IACV and FITV.

 

Thank you. What is a FITV and yes the CEL is on, i'm going to check that when i get back from out of town

 

Here are links showing how to clean the FITV and IACV.

 

mine does the same but when i unplug the iac valve it misses between 1500 and 2000 rpm.i have cleaned the screen within the last 2 weeks and checked the gasket. my check engine light has always been on and it just started doing this recently. no recent mods. does this sound like the same problem or something totally different.

 

Pull the CEL code from the ECU.

 

i thought of that when i got home, the code is P0135--O2 Sensor Heater Circuit Malfunction(Bank 1 Sensor 1). That is the lower sensor. that sensor hasnt been ont the car since i got it (little over 6 mon. ago) Why would it just now start running funny? It will idle fine until it warms up enough to cut the fan on, then it goes from 1k to 2k. Its even choked itself out on occasion.

 

after you do that if it still isn't working......or you could do a cycle check for compresstion......when my head gasket went out the rpm in n or with the clutch in the rpm would jump going up and down......sound like i was reving my engine at stop lights and stop signs......so i would check your coolant level to see if your losing any..... just m 2cents should check ,not sure if this is going to fix your car

 

not using coolant or oil. A compression check sounds like an idea tough.one more thing i can check off the list. i have also heard check the egr and it could be worn cam gear and belt. but its not jumping time. and on the big trucks i work on, when the egr is bad it burns coolant and has a huge loss in power. i dont know if that translates to cars.