bfrederick78

I have an F150 V8 5.4. A couple weeks ago the truck started hesitating or missfiring upon acceleration from coast or deceleration. The check engine light came on and was throwing a bank 2 sensor 1 lean code. There is also high pitched ringing or hissing coming from the engine compartment while the cruise is set at 68-70 mph. The noise will go away with acceleration or deceleration. It has just over 95,000 miles on it so I decided to change the plugs. After the new plugs were in there was no change in the problem.

I took the truck to the local Ford dealer. They told me the oxygen sensor was bad and replaced it. No change in the problem.

They then told me that the left front cat was plugged and wanted to charge me $800 dollars (not including labor) to put an after market cat in. I went and bought the same cat from Auto Zone for $355 and replaced it myself in under an hour. No missfire or any other problems for over 300 miles.

Today the problem came back. The check engine light started blinking for a couple minutes and turned off. I turned around and drove another 20 miles home and no problem for those 20 miles. I haven't been able to plug it into the computer yet to see if there is a stored code.

There is definately a problem that still exists and I am hesitant to take it back to the same dealer. I am leaning towards fuel injectors but told the first dealer that in the begining and they didn't even consider checking them. I am going to replaced the fuel filter today but I doubt that is the problem because it seems to be only bank two that is affected.

Any suggestions would be greatly appreciated.

earnhardtfan7971

I had the same problem, I replaced the spark plugs which took 3 days because I broke one and had to wait for the tool to come in the mail. That didn't help so I replaced the coil yesterday, so far it has helped but will let you know. If this doesn't fix it I'm doin injectors next

Turkey Hunter

Well you should have a missfire code on there if the light was blinking. Check it and see what it is and post it back on here. I'm thinking a bad COP may be the problem.

bfrederick78

The codes are p0171 and p0302. These appear to be bank one codes and the problems I was having before were bank two (oxygen sensor and converter).

ZigZag

Do you have any updates on this problem? The 5.4 in my 2006 did the same thing yesterday while I was trying to pass someone on the highway and I'm pretty sure it's not just because of the cold weather (like gas lines or injectors freezing).

JLBlazin00

this is a very common problem from bad catalytic converters, vct sensors, plugs, coils, and injectors they all have the same symptoms good luck ive still had no luck at getting it fixed.... one person said cats so i cut those off ran a little better. still misfiring so plugs and coils next when i get paid again.... best of luck

Fireman1291

ITS YOUR FUEL INJECTORS. I went through the SAME crap last year. The code was the same. My Cylinder #5 injector was locked open. Ford replaced under the 100K fuel ink warrenty.

I also had my o2 connector on the passenger side become unclipped from the fire wall insulation underneath and the connecter fell on top of my header and had partially melted through. Then when I would hit a bump it would pop that fuse when the exposed wires grounded out on the header metal. It took forever to find he problem cause the harness is way up there and that one stupid fuse circut controls a ton of ****.

lx4life

this just happend to me today but I had p0171 and p0301, The cel light would lblink and the codes were only pending. I am changing plugs and maybe COP, but wanted to see what others did.

VTX1800N1

Blinking CEL = misfire detected. That rules out transmission problems. Get the codes read to figure out which cylinder. Swap the coils around between cylinders to see if it's the coil. If not, swap injectors. If not that, change the plugs. If still not fixed, do a compression test.

94f1504x4I6

I have the same sort of problem with my truck... from a stop acceleration average to slow it hesitates and chugs a little.. i have no codes and never have thrown any mentioned, my exhaust has no cats in it so cant be that, all four oxygen sensors are still in the truck. It also has that whine/humm/hiss noise at a coast then if you accel or decel off of a coast it goes away.. or maybe just cant hear over the loud exhaust when start to excel.
so with no codes, where would i start... dont really want to just throw parts at it.. truck has 60,000 miles on it.

thanks for any help guys