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View Full Version : 3v 5.4 intermittent hot idle issue



barnyard
01-11-2014, 03:56 PM
So my head is spinning reading through threads about trucks with symptoms similar to mine, but I figure it makes more sense to explain exactly what's going on with mine. The truck runs fine, smooth, no loss of power...for the most part. If I am towing my camper and come to a stop...even after less than a mile, the truck pulls fine but either dies or runs very rough until I hit the gas, rev it up and its fine and the idle stabalizes. Same thing if I do a lot of highway driving with no trailer, get off the high way and the thing runs real rough or dies, but only at idle, rev it once or twice and its fine. I kind of forgot about it because it doesn't happen when its cold, but today in the northeast we hit 51 degrees...i was on the highway and this issue came back. I run motor craft 5w20, changed the plugs, fuel filter and air filter. Still the same, engine works and this happens every time if its over about 45 degrees. Its never thrown any codes. I just don't know much about these 5.4 with variable can timing, I've read all kinds of threads about can phasers, timing chains and tensioners, but in most of those people mention getting certain fault codes. I might order up an oil pressure gauge so I can monitor what its doing, but I'm hoping someone has some other explanation for me.

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Oh, and its an 07 with 120k on it.

RhinoZ24
01-11-2014, 04:08 PM
If its idling issues, try cleaning your throttle body and your IAC (Idle Air Control) Valve. Sounds like that might be the issue here.

barnyard
01-11-2014, 04:38 PM
One thing I hadn't checked yet is the throttle body/IAC, I'll try cleaning that before I get too worried.

RhinoZ24
01-12-2014, 03:37 AM
Yeah easier and cheaper fix too. The IAC sounds like the culprit but I would clean both anyways just to be safe.

barnyard
01-12-2014, 09:58 AM
Now my understanding is that these motors don't actually have an IAC, I haven't gotten to cleaning the throttle body yet but just curious if there is a reason I would only have trouble when towing or long periods of highway driving?