01 F150 5.4L. Truck just started bucking/missing/hesitating throughout the whole RPM range. Popped the hood and could smell antifreeze. Upon further inspection, I have what looks like a pool of antifreeze around the #1 cylinder injector bung. From what I can see, no hoses are leaking up top. No codes are being thrown other than P0171 and P0174 (Banks 1 & 2 lean). I am starting to think blown head gasket or cracked head, but wanted to double check first.

Side note: Oil pressure and temp. are steady throughout. Truck has 204k, plugs were last replaced by previous owner at 100k (plugs and coils are on the to-do list).

Any thoughts on the matter? Thanks, it's appreciated.

 

If you see coolant it's coming from some leak in the engine bay.
Often times it will dry up quickly with engine heat and be more difficult to spot.
If it has gone on long enough there should be stains and visual acccumulations at the leak point.
Find the source of it first. Look the radiator/hoses over good for signs.
The fan may be blowing the leak over a wide area.
It may be your 'general' misfire cause from accumulation of coolant in some plug wells.
The second problem you have is an air leak in the intake tract at some point causing the 171/174 codes. Rotted/ hard rubber fitting?
With the miles the truck has your likely have some hose rot/ hardened/ cracked that need replacing.
Good luck

 

Thanks for the info Blue

Just an update on this. I had a friend of a friend who owns a repair shop take a look and scan it with his high dollar diagnostic scanner. The upstream O2's were extremely lazy, and dipping down to the 30's. The antifreeze (from what I was told) is due to an intake manifold gasket leak, which would also be causing my vacuum leak as well. I believe this to sound correct, as I had an intake manifold gasket leak on my Trans Am that was causing me some similar issues (sans the antifreeze). There were no misfires detected or any other codes thrown, so that relieves a lot of my worries.

Next question: What is the average price for an intake manifold gasket to be replaced at a shop? I am currently working 12 hour days, 7 days a week, and just do not have the time to do this myself. I assume this would be a good time to replace the plugs as well? Thank you for your input, it is appreciated.

 

https://www.ford-trucks.com/forums/8...d-on-5-4l.html

 

Well it wasn't the O2's. Truck is still "missing" (no misses have actually been detected) or "bucking", however you want to look at it. We cleared the P0171 and P0174 codes, and they have yet to come back, but I am betting on them doing so. I guess my next plan of action is checking the fuel pressure and seeing what I have there. I wasn't entirely sure how the O2's would be causing a lean condition, but I just took the mechanics advice as I thought he would know. Now I am positive that I have a nasty vacuum leak (still thinking it is the intake manifold gasket) or a dirty/clogged fuel filter.

The only hose that was rotted/rough was the hose that went from the intake manifold to the EVAP canister. Anyone know where I can find this hose? Will a rubber fuel hose work just as well?

Anyone have any other suggestions of things I should check?

 

O2 sensonr, fuel filter.....well, are you looking at for the code or worried about the antifreeze leak. If you have a leak that is a major problem and could be the cause of other problems. I think i would look more closely for the source of the antifreeze leak.

 

$845 later and my truck is now fixed (not including the $180 for O2 Sensors).

My plugs were junk, and one of them was even cracked. The antifreeze was coming from one of the coolant ports on the front of the intake, next to the #1 injector. The "lip" that holds the o-ring in was busted off in 2 spots, so even a new intake manifold gasket would not have helped my cause. Ended up replacing the lower intake with a new one.

Anyways, thought I would share in case someone has a similar issue down the road. Thanks for the help fellas, it is appreciated.

 

yep, see the photo in the link i posted above. Dont know if its common, but several guys have said they had the same problem.

https://www.ford-trucks.com/forums/8...d-on-5-4l.html