PDX-944

1984 944 N/A

Heres the deal. since ive bought the car, it idles at 1000 cold, 1500 hot. if i tap the gas, the idle will drop to 1000. if i tap it again, it will go up to 1500 again, and so on. i can put my foot behind the pedal and pull, and it will drop to 1000 and stay there. car has run great minus the high idle.
my cruise control does not work - this applies later.
i replaced my intake mani gaskets today, and disconnected my cruise control cable at the CC motor to do it. then reinstalled it when i was done. then my idle was at almost 2k.
i couldnt figure it out for a while, then it hit me that i hadnt put the CC cable in the same adjustment, it was a little off. so i readjusted it to idle at 1000. i can basically adjust the idle with it though. tighten the CC cable and it idles higher, loosen it and it idles lower. if i disconnect the CC cable from the motor, idle drops/car dies. is this normal?

also, before, if i pulled on the throttle cam (like the gas pedal), the idle would drop to 1000. now if i pull it, it will drop lower and die. i did clean a lot of crap out of the TB today, and im wondering what could cause all of this. should the CC have that much control of the idle? should i adjust the idle with the CC cable disconnected? should i just reset the idle completely and leave the CC how it is?

forgot to mention the bucking. i drove it about 80 miles after doing the IM gaskets, and it drove fine. then i was cruising along and it bucked numerous times, then died. fired right back up.
it was driving fine again except bucking randomly. died one more time.
i pulled over and fondled some wires and tubes. it apparently liked that because it drove fine after that. so thats not my main concern..

PDX-944

Okay so the bucking is awful today. I almost can't drive because it happens in bursts. Then it will run okay, then happen again. Ideas? I had a few seconds to poke but I'm in a job now.
I think it gets worse when I jiggle the plug on the AFM but I can be sure yet.
Ideas would be greatly appreciated.
It bucks some. And then sometimes will die when I let off the gas. Always fires right back up though

44cupmaster

PLUGS AND WIRES AND REPLACE THAT THROTTLE CABLE . also check and make sure that you dont have and vacuum leaks .

Hollywood D

Could be a fuel issue. IE, not getting enough.

xsboost90

ok so the cruise should have nothing to do with the idle. If cruise doesnt work, first off pull the cable off so it doesnt interfere. If the TB is super dirty, you may want to pull it and clean out anything that could be blocking air at an idle. There is an idle adjustment screw on top of the TB- is that in place? Also, check the throttle position switch on the side of the TB- it should click as soon as you turn the TB from closed. If it doesnt, it may be stuck in a non-idle position and that would cause some issues.

xsboost90

also- make sure the door inside of the afm is free- moving easily. Sometimes when your filter is gone/etc it gets dirt into the door area and restricts movement. Spray a small shot of wd40 down in the bottom and swing the door back and forth a couple times to make sure its smooth and free.

PDX-944

Thanks guys
So for the idle thing. If I unplug the cc cable, it pulls back in some and that kills the car. There are two screws on the tb. On holds the plate open, the other goes in vertically. Should the plate screw be adjust to hold the plate where it is currently, so that pulling the cc doesnt change it? Or do I pull the cc cable, let it die. Then adjust the idle until it runs?

The idle issue isn't causing the bucking. The bucking started after I did the intake mani gaskets. I found no leaks on anything. Plug wires are all on. I'll be driving fine for a bit then it starts bucking for a while.
It has to be something related to what I did. But all hoses are back where they should be and I didn't really unplug anything

Jfrahm

Bucking is often unmetered air getting drawn in, like from a cracked intake hose (J boot) or alternatively from AFM problems as Dan suggests. If you go through the AFM you might consider re-tracking the wiper contacts, there are some writeups and a youtube vid on that.

Fara

... or swapping to a MAF instead

*shameless plug of rogue tuning*

PDX-944

actually just a few days ago i watched that video on retracking the AFM, ive been curious about doing it since. i will here soon.
the bucking has not happened near as much since i re-routed the AFM plug so it goes straight in, instead of bending the wires 90 degrees at the plug. yesterday it did it a few times in the morning. then after work i drove about 140 miles to and from my shop, and it bucked maybe one time that whole time. the trip back it didnt do it once.
i did manage to figure out my strange fast idle problem. i adjusted my CC cable to add more slack, because it was actually holding my idle up a tad. i also unplugged the CC motor because sometimes when id start the car the cc motor would start clicking like mad. then stop when i push the brake, and start again when i let off the brake... weird.

mytrplseven

Here's a bit of info to consider, since I've done it all myself: Under the "J" boot there's a plastic "T" fitting that you can't see from looking at the motor. It could be broken, as mine was, or the vacuum lines attached to it are loose. The big thing I did is to plug a 2" pvc cap into the intake side of the "J" boot with an air fitting threaded into it. Clamp it and apply around 10 psi of air pressure into the fitting. Spray a mixture of soapy water all over the engine and look for bubbles. Areas of interest that aren't so obvious: Throttle body shaft, cannister next to battery, temp sensor and air stabilization valve (both under the intake manifold) and any "T" or "Y" fittings in the vacuum system lines. If in doubt as to the location of the fittings and routing of the lines, go to Clark's garage for a diagram. The connectors for the TPS and the AFM should be cleaned with an eraser where possible and contact cleaner spray. The AFM rebuild articles you can find online show how to bend the wiper on the tracks and cleaning the "barn door" to ensure it isn't sticking. Sounds like a lot to do but it really isn't. The cost of the pvc fitting and air fitting should cost you less than $5 (cheaper than shop rate at the dealer).