Idle question...

[ggmx3]

Help! Has anyone had this happen? I have a 92 V6. When it's cold outside, 20 to 40 degrees F, the engine starts fine, warms up fine, idles fine. Then, after the coolant has reached its normal operating range, the idle starts to hunt. It fluxuates between 300 and 1700, or sticks at a high idle of around 1600, then drops to 300. It only does this when the car is in gear! (5 speed) I really don't want to take it to the dealer to have them spend 8 hours on the computer only to tell me it is something simple. Please help.<P>TIA

[cmx3d]

Hey i have a 93 v6 auto, and had the same problem but got it fixed. i went to valvoline and they said they could fix it. it was probally simple enough for me to figure out how to fix but oh well. they cleaned my valves, and intake manifold. after a week or so it still had the ruff idle. So i look under the hood and noticed the pcv valve wasn't plugged in, and the intake hose wasnt tightend to the engine. After i fixed that easily myself the bad idle stopped. But i'll tell ya one thing, i'm not done with the bastard's at valvoline that tried to screw me over! hope this helped

[David Coleman]

PCV is definately a posibility. I know my car does this due to a malfunctioning IAC [that thing on the bottom of the TB].

[syuoak]

My 94 does the same thing. At "idle" it fluctuates between 300-1500. I took it to the Mazda dealer to see how honest they would be. Their explanation was that it needed a new throttle body ($700 + labor) as the idle sensor inside that has a coolant line with it was clogged and can't be cleaned or the sensor can't be replaced....need the whole thing. Does cleaning the valves and intake really help??

[ggmx3]

Cleaning my throttle body did NOT fix this problem. Neither did replacing the by-pass air control (BAC) valve (that's the thing on the bottom of the throttle body - and yes, it can be replaced separate from the throttle body. ~$425US). I had the car at the dealer last week and they said nothing is wrong with the car - they could not duplicate the problem. When I picked the car up I asked how long the warranty was. They said 12/12. After several blocks it was obvious that they had done nothing. The idle still hunts. I will have the car at the dealer on Wednesday, as far as trusting them not to rip me off - they WILL honor their warranty. Good luck with yours. I'll keep you posted.

[jasonbierschwale]

Hey man, <BR> I just replaced my clutch this past weekend. After putting everything back together, I had the same problem you do... I hunted for hours for a vacuum leak or an unplugged sensor... until I got frustrated and went inside. When I came back out, the first thing I saw was a rip in my air intake hose (the one that goes from your air cleaner box to the throttle body). When I let the clutch out, the engine shifted, opening the crack even more, and almost killing the engine. Always check the simple cheap stuff first... there are several places where that hose could leak. Just my $.02! [img]shrug.gif"%20border="0[/img]

[Frenchguy0]

yes a few months ago that question was already answered. Check all the hoses coming from and out of your intake/ air box. If one has a hole or crack, it will cause the engine to get more air than supposed, getting the MAF?VAF system all crazy, causing your idle speed to jump up and down.<BR>Also, when my hydraulic tensioners went bad (they support the timing belt), i noticed that the idle speed was jumping on and off real bad and then the engine was stalling.<BR>I would check your hoses first and clean everything with your intake/air box (filter) [img]shrug.gif"%20border="0[/img] <BR>my 2 cents. I'm no mechanic but that's what I know from behind on this board for a few months.

[ggmx3]

Thanks to everyone for your replys. I have tried all the suggestions - I still haven't found the problem! Round two with the dealer is tomorrow. I'll keep you posted.

[ggmx3]

Okay, round two at the dealer. The car is still not fixed. Now it won't even start! I am very mechanically inclined but this one has me stumped. I've tried everyone's suggestions. Anybody got any other ideas?<P>TIA

[ggmx3]

I got the car back from the dealer today. It seems to run fine. The culprit was the distributor. I don't understand why it caused the problems I had, but at least the car is fixed. Thanks again to everyone who replied.