Its a really simple part. I've been using the Autozone IAC for going on 4 years no issue also had one in my van. If you really want the Motorcraft IAC Rock auto has it for $67

 

The best thing to use to clean an IAC is WD-40.

 

FWIW the 35 mile drive to work was flawless as far as bad IAC symptoms go.. i am still going to replace it tonight.

i will report back after replacement. i plan on clearing the KAM while i am doing the install.

 

******UPDATE******

i replaced the IAC with a new motorcraft unit from ford on monday. i also disconnected the battery for 45 min to clear the KAM.

i then reconnected the battery, did 2 drive cycles.
the next morning it started fine and started fine again at work without any additional cranking. wednesday was the same and so was thursday.. at this point i thought my problems were cured. This morning (friday) after the truck sat for 15 hours in my garage, i hopped in and tried to fire the truck up. it cranked about 3 times longer than normal before it finally cought and fired.. i got out and saw a rather large cloud of smoke in the garage (obviously froma rich condition) it smelled rich and not like oil. went on with my drive and we will see how tonight leaving work goes.

at this point i am almost certain that the hard start is fuel related due to the cloud of smoke when it finally starts.
as mentioned earlier leaking fuel injectors and possibly a bad fuel pressure regulator could be the cause.

tonight i am going to try and rent the fuel pressure test kit from autozone and do the regulator test as well.

is it possible that an injector can leak intermittently?

 

Last week my mechanic friend has a couple minutes to pull the mode 6 data. he found that cylinders 1, and 5 had 245 misfires recorded in 16,000 allowable x 2 drive cycles to trip CEL. cyl 7 had a recorded 145.


any connection?

 

Trouble starting, blowing smoke, misfires...? You make it sound like the truck turned into a total lemon over the course of 6 weeks. Are you still daily driving it? Any updates?

 

update

i sent the fuel injectors out to be serviced / cleaned at lindertech.com. they called and said they did not find anything faulty. none the less i had them do the full clean in case something was contaminated inside the injector.

i had the battery disconnected overnight while i waited for the injectors. Got the injectors back and installed them put everything together and drove it for about an hour total stopping a couple times in between to ensure i got my (2) drive cycles in. all was well yesterday, this morning i hopped into the truck and drove 2 min to the park by myself to get the kids outside. we played for an hour then went to leave. same condition as before. i cranked about 5 sec. it caught stumbled a bit then died. i cranked it again and it caught after about 4 secs. it puffed black smoke for a second then cleared. i drove across the parking lot and popped the hood and checked for fuel in the regulator / vacuum line, nothing it was dry. it fired right up and off i went. when i left this morning i had the scangauge2 on closed / open loop operation and noticed that it was in open loop for about 20 seconds before switching to closed loop.. is that odd? the truck has sat in the garage for about 18 hours so i know it was cold.

 

Twenty second open loop on cold start ( under ~140 ) is correct.

 

it is doing it when cold and sitting over night now, so now the hunt changes a bit.

the fuel system pressure is within specification and raises with vacuum removed at the FPR. the system also holds pressure indicating no bleedback to the tank or leaking from the injectors.

i have been reading about the cyl head temp sensor. could this sensor table the computer to dump more fuel at startup when cold? if it were telling the computer that the engine was like 30 below would the pc dump more fuel for a cold weather start?

thoughts?

i am trying to think of things that would cause the computer to cause a rich fuel condition on start up?

 

update.

the fuel pressure will bleed off approx 5 lbs in 1 hour.. not much but still enough to cause an injector drip.
here is what has me thinking faulty injector again.
i can mimic the problem start up by the following; run truck to operating temp then shutdown for 45min - 1 hour. it will have a hard restart every time.

i tried this about 6 times to confirm and seemed reliable; pull the intake tube off and shoot some compressed air down the throttle body before i try restarting (fuel vapor can be detected), if i do this it will restart fine every time. if i dont hit it with compressed air it will have a hard re-start. this to me seems like risidual / introduced fuel into the cumbustion cbamber before key on. this could be from a leaking injector or possibly the purge canister / valve being saturated.

interesting sidenote. since i got the injectors serviced at Lindertech the problem has increased 10 fold. they did test the ohm rating and cleaned the injector but i am not convinced they theroughly checked the bleed-off or leakdown
the oil is begining to smell like fuel so i am goign to change it before it gets too dilluted.

interesting sidenote #2. the baro is reading about 2,000 feet off in elevation from actual.

tonight i am going to tie off the injectors to the rail and test for bleedoff / leakdown again. there is ample room on the passenger side so i will test the passenger side first then rotate the drivers side injectors to the passenger side to test all 8.

anyone else have any thoughts?

 

If the injectors are dripping with the key OFF, they are bad, period.

 

If they leak a drop w/Key on, they're bad as well. There's also a chance of hydro lock, which in turn can blow the motor @ crank.

 

after another leakdown test with the injectors and rails pulled i found some minor dripping from 6 of 8 injectors. none would leak enough to officially "drip" from the injector. i swapped my full set of injectors for a known good set and i have been driving without issue for the past 250 miles.

do not have your injectors serviced at lindertech. i expressed my problem with my injectors and they assured me they tested fine.

at any rate i think i have this problem solved. i hope this helps others.

 

I think about 40 psi but I am not sure exacly. I was having similar starting issues, and depressed the schraeder valve to relieve the pressure just so the pump could hit the sweet spot and pressure up the line quite a few times after work to get home. A lot of those times I hardly got any pressure at all. Some times it would squirt all over my hand. I broke down and finally replaced the pump so I think I have that part done but I think I had a bad relay as well that may have played a part. I dealt with this problem for about 4 months before getting off my wallet and replacing the pump.

 

I'm having a similar issue with a rebuilt marshal 5.4L in my 00 lariat. Engine was installed march '10.

The problem started just having an issue starting after work, and it's not consistent every day. It seemed to really be an issue on the hotter days.

It turns fine, revs up to 1500 then down to 300+- and dies. The idles is a teeny bit rough when this is happening. If i kept throttle down a little it would stay running and i could put it in drive and it drives great. Gas mileage is normal. I can experience the issue, drive 5 min's down the road, stop, and it will restart just fine.

This started only being an issue after work, now sometimes in the mornings it will do the same thing except it doesn't die. The problem is especially bad when it's 90+ degrees out.

Unlike Cobra5laddict, i never see any smoke. If i give it throttle trying to start, it feels a little rough but is smooth once i get going. If i let off the gas before putting it in drive and going a few feet it will die. So typically once it's in drive, it doesn't die.

I was thinking i had another coilpack going bad (because of the rough idle) until i came across this forum. The marshal engine has about 40K on it. Some of the parts however have 230,000. Does this sound similar to cobra's original issue to warrant pulling the fuel rails/injectors?

I'll be cleaning the IAC this weekend since that seems to be an easy fix. Before i go messing with fuel rails, injectors, and the flux capacitor wanted to make sure i was on the right track. Thanks guys... money's tight so it's all up to me and my novice knowledge.