Low idle rough start

Lancsta · 06-16-2009, 03:10 PM

When i start up i gave to give it some gas to stay running, like you would an old truck with no choke. Replaced plugs, wires, cap rotor and also cleaned the IAC. I recently cleaned the TB and the intake manifold with some seafoam to try to clear any carbon. Once it warms up I seems to run fine, unless I'm in drive, or am coming to a stop. I've searched and searched the forums and google and everything I try doesn't seem to work.

88YJtoCJ · 06-16-2009, 03:30 PM

what is your idle starting, and your idle one its heated up...

Lancsta · 06-16-2009, 03:54 PM

After it's warmed up around 750, cold start it idles around 200. I also replaced the battery cables after noticing they were loose and corroded. No change. All vacuum lines are in good condition.

Lancsta · 06-16-2009, 09:11 PM

Cleaned the upper O2 sensor and replaced the TPS; still no change. Guess I'll buy a new IAC in the morn and see what happens.

Also it still wants to stall when I stop. Anyone find a fix for this yet?

trippleb · 06-16-2009, 10:37 PM

Hi there I was having similar problems with my jeep and another forum member suggested that I tune the carb with a Vacuum pressure gauge. Yesterday I hooked up the vac. gauge to the manifold and started the jeep, with someone in it giving some gas so it will idle adjust the 2 screws on the bottom front of the carb so that it will idle by it self, then fine tune to the highest Vacuum rating you can get (I think it was around 450 - 500)
I then adjusted the timing to around 8-9 degrees and I has been running great and idling around 1250 rpm and I no longer have to give it gas when i put in the clutch to keep it from dieing, hope this helps you too.

-Bryon

bigbelman2009 · 06-17-2009, 01:19 AM

i am having the same problem on my 2.5 and i have yet to find a solution. please post what you find

Lancsta · 06-17-2009, 09:16 AM

You know that's a good possibility with the injectors and TB that I would need to adjust the timing and idle. I believe it's runnig a little rich anyhow and hadn't thought of doing that. New IAC shows up on the 18th, I'll post if I get anything new.

On a side note, I swapped out the TPS I had from the 4.0 TB as a spare and it seemed to have fixed the 200 rpm cold start.

Lancsta · 06-18-2009, 07:52 PM

I've found victory; Atleast for the moment. I recieved the new IAC, threw it in in he parking lot. At first it ran at about 2000 to 3500 Rpms, but after a short drive home about ten minutes; waiting at a light she dialed in and idled just fine. Don't get your hopes up yet, I'm going to give it a few days to consider this one solved.

Now on to the rear spider gears.