travlnman

2010 F150 with 4.6L 2V , 4spd auto. What should my idle speed be , when up to operating temperature in both park and in drive while stopped ? I feel mine is a little low, at around 600 rpm in park, and in Drive while stopped with foot on the brake, it can dip as low as 500rpm. Thanks for your help !

21RRF150

iTrader: (1)

Well if it make you feel any better...I have the same engine, 4.6l 2v...mine runs around 6-700 at idle, and 5-600 in drive, at a complete stop, just like you.

travlnman

mbullock, thanks. My primary reason for asking is an annoying thing that started about 10k miles ago. I have started threads here and other forums about it, but no good has come of it. With my AC on and in D while stopped (or park for that matter) the idle is really rough feeling, almost like it is not idled high enough. Makes me wonder now, if the AC compressor may be going away... I hope not.

21RRF150

iTrader: (1)

I'm not sure if there's anything wrong with you truck. All I know is with ac on, I don't really notice any diiference in idle speed. I know its not rough...I would've noticed that.

travlnman

I bought this truck brand new, have put all 63k miles on it myself. This is definitely a new thing (the roughness, not the idle speed) . Up until about 10k ago, this thing was butter smooth at all times, now not so much. If you or someone else had told me their truck idled at , say 750 rpm or so I could blame it on the idle, but that does not sound like the issue. The roughness is coming from somewhere else. Throttle body has been cleaned, new air filter (stock paper type) new plugs etc, etc. It only happens with the AC on, primarily during the compressor "on" cycle...sounds like I may have answered my own question :/ Thanks for the info, I can never get too much input .

21RRF150

iTrader: (1)

Well I will def pay more attention tomorrow when I drive it. I will keep you posted.

travlnman

Thanks,but I think you would notice if it was this bad. Sadly, the dealer could not tell anything was wrong...but without a point of reference (many miles in the saddle ) I was skeptical of them finding anything anyway. No codes on computer, and I have even "cleared" the computer by disconnecting the battery and letting it relearn the idle and shift points for the trans. Even let it idle for few minutes with AC off after clearing, then with AC on, hoping it would sort itself out, but to no avail. I may do a little ebay shopping for an AC compressor...

Storm Trooper

my 09 4.6 has a rough idle at times also. my truck idels rough with the air off or on it dosent do it all the time. i am kinda stumped on this one anybody got any ideas?

Mike831

Have you tried cleaning the I.A.C. ? Idle air control valve

travlnman

Well, don't know about anybody else, but mine does not have an IAC, it has the servo controlled throttle, so no IAC valve. That would have been my first suspect...:/