2005 F150 5.4L strange misfire and lean/rich codes
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06-18-2018, 03:21 PM
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2005 F150 5.4L strange misfire and lean/rich codes
Hi everyone I am really in need of some help, I have been trying to figure out what the issue is with my truck (2005 F150 with a 5.4L). It has 145K miles on it.
To preface: I'm really lost, I have been working on cars for many many years now, and I can't figure this out. I work M-F at one job and Sat and Sunday another job, so I didn't have time to work on my truck and it's not my primary mode of transport (maybe gets 15 miles a week at most). It started having an issue and I took it to a shop because I just didn't have time to work on it.
So let me kind of give you a sense as to what is going on.
I got my truck and over time it slowly developed a tick on the top end, I initially thought it was a phaser or the timing tensioner that was going bad, but after bringing it to a shop they told me the cam was fried. The one lobe was worn down pretty bad, they sent me pics of the cam still in the truck, they told me a price to replace it, I agreed and they replaced the cam.
Now this is where the problems started when I went to get the truck back.... they were taking an unusual amount of time to get it back from when he said they were finishing up, so I asked what was up and they said they put it all back together and it had a misfire... They made it sound like it wasn't bad so I said okay and I'll come look at it. He said not to worry about paying for the rest of the work (I paid 1/3 up front for parts) unless the issue clears up (which was amazing of them and I really appreciated it). So I drove the truck home... and WOW that misfire was BAD. It would only happen around 1500-2000 rpms while driving (didn't matter if you were accelerating lightly at that rpm, decelerating, or keeping it there), and somewhat at idle. However if you're not at that RPM area it would not be bad, it would almost seem normal. The thing is that I get a few codes from the truck, One bank is lean, one bank is rich, random misfire on startup and random misfire code. The shop claims that they tried everything, but no luck. I am not sure what it could be, any ideas?
To preface: I'm really lost, I have been working on cars for many many years now, and I can't figure this out. I work M-F at one job and Sat and Sunday another job, so I didn't have time to work on my truck and it's not my primary mode of transport (maybe gets 15 miles a week at most). It started having an issue and I took it to a shop because I just didn't have time to work on it.
So let me kind of give you a sense as to what is going on.
I got my truck and over time it slowly developed a tick on the top end, I initially thought it was a phaser or the timing tensioner that was going bad, but after bringing it to a shop they told me the cam was fried. The one lobe was worn down pretty bad, they sent me pics of the cam still in the truck, they told me a price to replace it, I agreed and they replaced the cam.
Now this is where the problems started when I went to get the truck back.... they were taking an unusual amount of time to get it back from when he said they were finishing up, so I asked what was up and they said they put it all back together and it had a misfire... They made it sound like it wasn't bad so I said okay and I'll come look at it. He said not to worry about paying for the rest of the work (I paid 1/3 up front for parts) unless the issue clears up (which was amazing of them and I really appreciated it). So I drove the truck home... and WOW that misfire was BAD. It would only happen around 1500-2000 rpms while driving (didn't matter if you were accelerating lightly at that rpm, decelerating, or keeping it there), and somewhat at idle. However if you're not at that RPM area it would not be bad, it would almost seem normal. The thing is that I get a few codes from the truck, One bank is lean, one bank is rich, random misfire on startup and random misfire code. The shop claims that they tried everything, but no luck. I am not sure what it could be, any ideas?
