Please Help!

Truck: 2001 F150, 5.4, 4x4, crew cab, 171k miles

Current Problem:

• Very Rough Idle / missing
• P0308 Misfire #8
• P0174 Lean Bank 2
• This says to me vacuum / intake leak. I have sprayed brake cleaner all round and did not get a change in idle

Video:
I think that noise sounds like a vacuum leak. More specifically like they did not re-install the intake properly / gasket didn't seat well / over torqued and cracked the intake / etc. (see below)

Important History:

• Truck was running fine before I took it to a mechanic
• Had an oil leak from bank 1 valve cover gasket and intermittent no-crank, no-click, no-start.
• Had them change valve cover gasket on bank 1 and install a new starter.
• Mechanic called me and said there was a coolant leak at the intake manifold. Not surprised as this is a common issue. I said to go ahead and replace the gaskets and let me know if the intake was cracked or not. They called and said the intake was NOT cracked.
• After they replaced the intake and water channel gaskets (assuming they did this), they called and said the head gasket was blown / head was warped and tried to get me to add "Fiberlock" head gasket sealer to the coolant.
• I said it was running fine prior to their work and I never add "magic chemicals" to my coolant.
• The truck NEVER overheated. Temp has always been rock solid.
• I told them to stop work and took the truck back.
• The oil is perfect, no milky consistancy
• There is no blow-by or discolor in the cooling fluid
• No white smoke from exhaust

I am at a loss. Please help!

 

 

Thanks for the reply pdqford. They didn't say. I did ask if they had done a compression test and what the results were, and they said they didn't. I was short for time (and short for patience) so I had my son (it's my sons truck) just take the truck and leave. (I was handling this from work over the phone while my son waited at the shop all day)

I have not done a compression test myself yet and I haven't done a real-time scan. Don't have the tools. At this point I am thinking of just taking it to the ford dealership and hoping for the best (unless anyone knows of a great & trustworthy mechanic here in Tucson, AZ who knows 5.4s backward and forward)

I was hoping that the sound it's making would sound familiar to someone on this site. It sure sounds like an intake leak to me (with my limited experience). This, coupled with no other sign of head gasket issues (No...white smoke, milky oil, blow back and/or discolored coolant, over heating, and it was running great when we brought it in, etc) make a head gasket hard for me to swallow. Since they removed the intake my money was on intake / vacuum leak, which from the sound I would think is substantial. But my brake cleaner spaying effort did not yield a leak.

 

If the engine codes you have are current you really should fix the misfire on cyl 8. Your pouring raw fuel into the catalytic convertor and may burn it out. It's also the same bank as your P0174 code. Your pic shows the AEM tube to throttle body, large clamp area, looks like it should be re-positioned for a better fit. You might also want to clean the MAF sensor if it hasn't been done before.

 

Thanks Lime1GT. My son is not driving the truck for the reasons you pointed out. I did notice the clamp on the intake tube. I will adjust tomorrow. I cleaned the MAF about 6 months ago, but will keep that on the option list.

 

I set an appointment with another shop I have used in the past. They are going to do:
I sent them the link to the video and the info I posted above. I am impressed with the service, as they had a tech listen to the video and they responded to my email before the truck is even at the shop.

Here is what they said....
"I had one of our technicians listen to the video and it does in fact sound like it is sucking air. We'll be happy to take a look and see if we can find a vacuum leak first. "

I interpret this to mean, "..it does in fact sound like it is sucking air." as I does sound like a head gasket......and...."We'll be happy to take a look and see if we can find a vacuum leak first." as we don't think it is a vacuum leak, but we will look for that first. Fair enough.

I NEED YOU GUYS TO GIVE ME A PERSPECTIVE CHECK HERE, PLEASE! If I am off base, please let me know.

I am really struggling with the fact that the truck was (for last 2yrs) running great all the way up to pulling in their parking lot. They pulled the truck from the parking lot, into a bay and it didn't drive again. (no test drives)

Then, after they,
It suddenly has a head gasket leak (on Bank 2) that is so bad that it idles very rough and barely drives.

Couldn't this same sound ("sucking air") be because the intake track for #8 didn't get tightened down or seat properly on the gasket, or is cracked? Seems more plausible based on the work that was done, doesn't it??

I am just trying to apply logic, probability, and the little bit I know about wrenching to the situation. If I am wrong, off base, and/or missing some kind of key mechanic knowledge/experience, I am asking for you guys to help me understand.

Thanks.

 

Just to add, or maybe clarify; when you "spray the intake" with carb cleaner or favorite flammable aerosol, to see if you can get the engine to smooth out searching for that vacuum leak. This rarely works with modern ECM controlled engines, the ECM reacts too quickly and adjusts for us to pick up on it. Usually you need a scanner that has the ability to read live data , specifically short fuel trims (SFT). Then spray and watch the SFT react. Some report to use a un-lit propane wand with better results. Another way is to make or buy a smoke machine and watch where smoke starts to seep out.

I was also wondering how the 1st shop determined that the intake manifold was not leaking and like pdqford, how they determined it was a head gasket?. I just replaced the whole intake manifold to fix my Thermostat /cross over leak. Apparently they just installed those specific gaskets /seals or was the whole intake removed and all gaskets replaced?

There is not a lot of extra room to slide the intake manifold in or out....so it is possible that the 1st shop messed up a gasket on the reinstall . if they indeed remove it? secondly, those plastic intakes can get brittle as they age and would not take much to crack them. It does appear that maybe the intake manifold has been replaced before?? OEM ones generally had brass inserts embedded for all the bolts to thread into them. I didn't see any as the camera came around the passenger side. Maybe they came out and why the top cover was not on? IDK IF.... that Intake manifold had been replaced prior?? Then it might roll into question the quality of the aftermarket intake manifold??

 

enriched&beyound - Thanks for your response! Great information. I didn't know that about my "old" V Leak detection method not necessary working on newer cars. Makes sense.

Same answer I gave regarding their answer on the how do you know it is the head gasket, applies to the intake leak....they didn't/couldn't answer how they knew.

Great info on the intake gaskets, how they can be problems, and how to check. Thank you.

 

UPDATE: RESOLUTION! AND GREAT NEWS!

The new shop put the truck on the computer and found that the coil on #8 was working, but the FUEL INJECTOR wasn't firing. Turns out the first shop didn't connect the connector for #8 fully. That was IT! Was a very weird sound it was making for that to be the issue, but my son drove the truck home and said it is running just like it did prior. : ) They also did a smoke test for V Leaks and didn't find any.

Something else you should know about the original shop...Even though the person I talked to said they did NOT perform a Compression Test when I asked, my son said the mechanic called him into the back at one point and showed him some gauges saying "this was the problem" (one reading being lower than another). When I described to him what a compression test looks like, he said yes that was exactly what it looked like they were doing.

I will NOT be going back to the original shop ever again!

Thanks to everyone here for their help and support!

 

That's SUPER that it was a easy fix....Thanks for reporting back!!