2001 sport idle/jumping problem

[barfy]

2001 sport idle/jumping/lurching in gear problem

Hi all, I have a 2001 Ford Explorer Sport 4x4 6 cyl, 71,000 miles, Transmission fluid and filter changed @ 50.000. No check engine lights on, No oil leaks anywhere, runs great. Shifts perfectly,

The problem I am having only started 2 weeks ago, The trucks idles and run's perfect, But when I put it into first gear, it starts to idle real rough and every 5 seconds or so it lets a click sound like an AC unit kicking in (clicking only in first gear @ idle)
The idle goes up and down and the truck feels like it wants to move forward, If I am on the flat and I let my foot of the brake, it kinda lurches forward and then stop, then lurches ETC. It has stalled on me three times this week!!

It shifts throught the gears perfectly, both up and down, The 4x4 works perfect, Has any one any ideas on this as I am getting worried that it may be a failure coming on.
Really apprecite any ideas on this. I searched the forum and didnt find anything on this....

Thanks...

Paul..

 

[barfy]

*update*

I searched the forumsand I cleaned the MAF and the IAC sensors and no difference, So I blocked the wheels and put on the brake and let the truck idle in gear and I found IT is the AC unit clicking in and out..!!!!!
So now i have no idea as I dont even use the AC, If I turn on the AC with the truck in gear it still clicks in and out.....

Oh well, At least its not the Tranny..

Mods can close this thread if you like.....