hard cold starting (no idle)

[fgump]

Hey folks. First post here. I have lurked a while, since I haven't had any problems yet with my '00 XLT 4.0 SOHC. Had a tough time starting this morning.

I noticed at startup yesterday evening leaving work, it stumbled at idle a little, but it did idle pretty normally. Nothing seemed unusual. Drove 3 miles home, parked in driveway.

Went to start up this morning, and engine would turn over, fire, then shut back off. It did this repeatedly, every time I turned the key, it would fire, then shut back off. If I held throttle open just slightly, it would continue running. Let off throttle and it would stall out.

I checked connections of plug wires, MAF sensor, and ECT sensor, then restarted holding throttle slightly open (not above 1000 rpm). Finally, it's like something clicked, and the idle returned. I shut it off, restarted, and it idles like a champ.

Any ideas? MAF sensor? ECT sensor?

Thanks in advance.

Bill
'00 XLT 4x4 4.0 SOHC, 39,980 miles

 

[fgump]

Problem solved (?)

Cleaned IAC this afternoon, it had a little gunk in it. Used some carb cleaner, then blew it out with an air hose. Reinstalled, and hasn't been a problem tonight on a few errands. I'll see what it does in the morning.

Guess I should have spent more time looking around previous posts, as I found about 30 references to poor idle and IAC. I'll get there someday.

Thanks.

Bill

 

[jcd4]

Man, I thought I was losing my mind!

My '99 Sport 4.0 has been doing the same thing. Took it to the dealer, but of course by then the engine was warm and they couldn't find anything wrong.

I've found that if let the engine warm up to operating temperature (by keeping my foot on the gas) then letting it stall out and sit for 30-40 minutes it'll start up and run perfectly.

Thanks for the lead. I've been lurking a while looking for someone with the exact same problem.

What was involved in your cleaning of the AIC?

 

[fgump]

I have the 4.0L SOHC, so I removed the plastic shroud over the intake manifold. Two screws and remove the cruise control cable from the clips on the cover. The IAC valve is the cylindrical thing on top of the black intake manifold, center, towards the rear. With engine off, key OUT of ignition, unplug connector from valve. Remove any dirt buildup around the area before removing valve. Remove two screws that hold valve to intake, and carefully lift up.

Use some O2 sensor safe carburetor cleaner (if such a thing still exists!). I used pyroil, but I don't think it was O2 sensor safe, so I blew it out really well with compressed air before reinstalling.

Installation is the reverse of removal.

Hope that helps. I haven't had a recurrence since this posting in May.

Bill