Unsteady Idle

[Ibanezplayer272]

Hey guys. Ya im back with another question.. haha Well its nothing major. Anyway at idle the rpms go up and down a tad bit, probably not even a whole 150 rpms but if I look at the RPM gauge it visibly moves up and down, I dont have a cam and I pretty sure it didnt do this when I got it, I was thinking maybe spark plugs are gapped a little wrong, cause I changed those not to long ago and thats about all I did to the engine, whats your guyses take?

[fast64]

have you checked your vacuum lines? sounds like you may have a leak, one of them might be disconnected.

[Ibanezplayer272]

Are you talking about the pipe that goes to the the exhaust? It looks like it is apart of the A/C and I was thinking it was a vaccum pipe... I have messed with that lately because the clamp wasent tight and it came off and it sounded like I had an exhaust leak again so I checked after I got home and it was off of the exhaust so I put it back on and tightened the clamp pretty good so, I dont know...

[fast64]

no, the vacuum lines are little rubber tubes all around the engine bay, there is a junction on the fire wall, its a black thing w/ 4 vacuum lines coming off it, follow them from there.

[Scut95]

Hey there.....if any of these haven't solved the problem, it could also be your iac motor. My 95 does the same thing and i was told that this is the culprit. You can take it off and clean it out with some brake clean or even replace it.

[Bane-]

just go down buy a thing intake cleaner (not carb cleaner) for efi engines, take your intake pipe off. have someone hold the car around 2k rpms and spray the shit out of it in there. will clean the entire intake system from the iac to intake valves and flush carbon out of the exhaust. Just did this with the 90 and it made a noticable difference but the iac is to long gone to just be cleaned it seems. Need to follow vacuum lines first before I go replacing the IAC since its $75. But your gonna have to replace your plugs again after you do the intake cleaner since it will foul some/most of them.

[Ibanezplayer272]

Hey guys. Umm ya I checked the vacuum lines and all seem to be in good order, sounds like I can try cleaning the IAC motor, where exactly is it at? I would use that intake cleaner but I just put brand new plugs in.

[Bane-]

its on the throttle body facing the front of the car. kinda shaped like a L with 2 bolts holding it on and wire connection. opposite side of the TPS I believe. but atleast it starts right for you. mine will start, try to idle once it goes to idle down it dies. gotta keep it up around 1500rpm or so for a couple sec for it to idle right. (only when its a cold start and hasnt been ran.

[Ibanezplayer272]

Hey Bane. Umm I havnt checked the IAC motor yet, I see the L shape, its metal, and it has the throttle cables on it, but im not seeing a motor or anything, if you can show me a pic or when I get home ill take a pic and you can show me where it is... Could my unsteady idle be at all related to how old my engine is? 177,000 miles...

[Bane-]

they call it a iac motor...everything is inside it..acts more like a sensor imho.

but yea, take a pic ill save it, circle it then post it back up.

[fast64]

you might want to do ao compression check on all your cylinders since your engine is that old.

[Ibanezplayer272]

K here are the pics... and if I want to do an ao check do I have to take it to a shop?

[Bane-]

im at work so i cant do nothin but...your 1st picture. where the intake tube connects to your throttle body. see the thing on the right where the vacuum/coolant line is that goes from the throttle body to the oil fill tube? its that piece under it. I thought it looked more L like in my head the other night.

[Bane-]

oh and you just helped me out, I need to bypass the coolant in the throttle body. just gave me a visual how to is that just a piece of pipe hose clamped in? what did u plug the holes in the throttle body with?

[fast64]

Quote: Originally Posted by Ibanezplayer272 K here are the pics... and if I want to do an ao check do I have to take it to a shop?

sorry, typing error, it was supposed to be A compression check. You can do this yourself with a $20 compression gauge at an auto store, Autozone may even rent them. You stick the "probe" in the spark plug holes for each cylinder and turn the engine over. Its not hard to do.

[Bane-]

here ya go anyway as promised.

[Ibanezplayer272]

Thanks Bane and fast64

Fast64 : Alright man thanks ill definately check my compression.
Bane : Hey umm is this what your talking about? I bought the car as is I havnt touched a thing under the hood yet. What are you talking about #1 or #2? I can find out for ya once you tell me what your lookin at.

[fast64]

number 1 is your throttle position sensor, number 2 is just your PCV tube, he is talking about the big cylinder thats under the PCV tube

[Ibanezplayer272]

Oh haha ya I know the IAC motor is that, I already took it off and looked at it cant clean it though gotta get brake cleaner tomorrow.. he was talking about bypassing the coolant on the throttle body im not sure what hes talking about, you know about the holes being plugged and what not...