Big hesitation off idle when cold - suggestions?

[Ozz]

My '03 MM had developed a serious hesitation off idle when the engine is cold. The engine runs a little rough at idle as well. Once the engine warms up, the problem seems to go away.
I have recently changed the plugs but the hesitation existed before and the new plugs did not help.

The car has:
New plugs (Autolite XP104 Iridium @ .054" gap)
K&N Panel filter (10,000 miles since I cleaned and oiled it)
Superchips tune

Does anyone have any suggestions?

THANKS!!!

[Rider90]

Does the idle ever raise or drop randomly at stop lights? I suggest an IAC (Idle Air Controller) - Mine is going around 40k, how many miles on your 03?

[hbarrett]

Any kind of oil at the air intake makes me suspicious of fouling the MAF wires and gunking up the throttle body, but the IAC may be giving you an early warning of impending failure. I had to replace the IAC every 20k to 30k on my CV
My '03 MM had developed a serious hesitation off idle when the engine is cold. The engine runs a little rough at idle as well. Once the engine warms up, the problem seems to go away.
I have recently changed the plugs but the hesitation existed before and the new plugs did not help.

The car has:
New plugs (Autolite XP104 Iridium @ .054" gap)
K&N Panel filter (10,000 miles since I cleaned and oiled it)
Superchips tune

Does anyone have any suggestions?

THANKS!!!

[Ozz]

I have ~33k on the car.
I had an incident last winter one evening after work where the car would not idle at all and would stall if I didn't keep my foot on the pedal. It 'snapped out of it' about 20 minutes into my drive home. It has never happened again.
What about cleaning the MAF - what can I safely spray on the wire?

I wonder why it only acts up when the car is cold now?

[hbarrett]

Your problem sounds like a typical IAC problem, easy to replace, or warranty repair. For MAF cleaning, CRC makes a cleaning spray - no residue (small spray can). You can buy it at most auto parts stores. Do a search, there are other message threads here dealing with cleaning the MAF.
I have ~33k on the car.
I had an incident last winter one evening after work where the car would not idle at all and would stall if I didn't keep my foot on the pedal. It 'snapped out of it' about 20 minutes into my drive home. It has never happened again.
What about cleaning the MAF - what can I safely spray on the wire?

I wonder why it only acts up when the car is cold now?

[grampaws]

I used iridium spark plugs in my old 4.6 sohc
I found I had a similar problem..I made the spark plug
Gap smaller and the problem went away..
Gap worked best between 0.45 and 0.50...
0.45 is what I would suggest...

[Ozz]

is .054 too much? That is what Autolite said to gap them on the MM...

[RF Overlord]

Ozz, .054 is the correct gap for conventional (which includes platinum) plugs. Iridium plugs, due to the extremely small tip on the center electrode (0.4mm), usually run a smaller gap, on the order of .044 or so...

[Ozz]

I guess I was misinformed. A couple of websites that sell spark plugs listed the gap for the XP104's at .054". I figured it made sense because iridium has a higher conductivity than platinum and a thin wire tip should improve the ability of the spark to jump, not impede it...
I guess I'll take care of the excessive gap this weekend.

Thanks.