very low idle and stalling (i am going crazy)

[danthemanx07]

well i thought i had my problem finally fixed last week with a new fuel pressure regulator and vacuum line, but apparently not. my problem is in gear, my jeep (fuel injected 318) idles very low, like maybe around 200-250 or something like that, and it will not idle for more than a few minutes before stalling, it seems to happen more often when the thing has been running for a while too

i have been through 3 regulators and a few months of aggravation with this problem, can anyone help?

[rccolacc]

Dan,
You're not going to believe this, but I had a similar problem happen on my '97 ZJ just yesterday. It has the 318 also. On the way home it would run fine, but as soon as I stopped and the engine died down to an idle, it would go way low (200 RPM) and sometimes stall if I didn't touch the gas. I have a factory service manual on it, so I went ahead today and tried diagnosing it. I figured it was throttle body related, not fuel pressure, since it only happened at idle. I thought mine was either the TPS sensor (Throttle Position sensor) or the IAC (idle air control) motor. The IAC motor ultimately controls the idle speed, but sometimes the TPS will go bad and tell the IAC motor to close, thus killing the idle down and killing the motor. Check your TPS with the key on and still plugged in. Put a voltmeter on the center wire and check for voltage between that center wire and the negative battery cable. It should be more than .3 and less than .9 volts. Mine was .6. Then open the throttle to WOT and check again. It should be around 4 volts. Mine was 4.5 I think. The TPS was good, so I figured my IAC motor was bad.
I went to NAPA and bought an IAC motor for $50 and put it on tonight. Jeep runs perfect now.
The IAC motor is on the back side of the throttle body next to the firewall. It's held on by 2 torx screws (T25 I believe). It's difficult to take out because it's by the firewall, but it can be done without taking the entire throttle body off. I just did it a few hours ago. It took 5 minutes.
It's wierd you and I have the same problem the same time. If it really is your IAC motor that's bad, I wonder if the cold weather might be killing them. Interesting.
Call me if you need anything. I'm home in New Orleans now. Next week I'll be putting in the axle. I'll call you when I start.
-RC

[danthemanx07]

thanks for the advice rc, i dont think it is my iac that is the problem, i replaced it a few months ago, but maybe the part is faulty, anyway, yeah this problem is driving me nuts, carl (swampy) and i worked on the zj all day yesterday with no luck, we still havent come up with a solution

[swampy]

Dan... Any updates on this yet? Is it ok now?

I was thining about you yesterday when I was looking at a Jegs catalog.. they have bypass regulators in there and I started thinking maybe that would work.. Since it will only divert the excess fuel back to the line and not all of it..

Couldnt find your number to call and see how things where going..

Let me know..

Carl