Rough Idle - 2007 4.2 XLT
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Joined: Oct 2015
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I'm going to change the transmission fluid, rear end fluid, stabilizers, and U joints now that Christmas is over. Maybe the OD low throttle is a transmission shake and the rough idle is just inherent to 4.2 F150s. My U joint is making a little noise. Damned if I know. I'm going to start it up and jam a crow bar beside the engine mounts and see if that helps with the shake at idle. Never know, maybe the mounts are bad. I may take it to Ford or a reliable mechanic and have it checked out after that as I have run out of ideas. Such is life.
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Joined: Jan 2007
Posts: 10,636
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From: Vernon, NY
Another thought... have you thoroughly inspected your crankshaft's harmonic balancer?
I'm wondering if something is happening and it is off just enough for the timing sensor to get incorrect readings from the reluctor ring which must be read by the crankshaft position sensor.
Or else it is the crankshaft position sensor itself.
I had to replace both my crankshaft and camshaft position sensors on another truck I own, but it was giving me appropriate codes. But the idle was funky as all heck leading up to getting the codes. Again, I was getting codes, thus telling me exactly what was wrong. You aren't getting any codes, which makes this a tougher one.
Although, another side of the coin, there is known issues with the camshaft position sensor on these engines. It is a combination of a camshaft position sensor with a synchronizer ring assembly. Normally when it goes or it's way south, it will chirp/squeal making it sound like a bad pulley, along with engine roughness in all ranges -- not just idle. But you should get a service light.
At the end of the day, you shouldn't be getting any backfires. Which is why I am leaning towards a timing issue.
Although, you can take it to Ford, they can run a diagnostic on it, and it's a 50/50 chance they will find something wrong. I want to say drive it until it gives a code instead of wasting time changing out electronics and the such.
I'm wondering if something is happening and it is off just enough for the timing sensor to get incorrect readings from the reluctor ring which must be read by the crankshaft position sensor.
Or else it is the crankshaft position sensor itself.
I had to replace both my crankshaft and camshaft position sensors on another truck I own, but it was giving me appropriate codes. But the idle was funky as all heck leading up to getting the codes. Again, I was getting codes, thus telling me exactly what was wrong. You aren't getting any codes, which makes this a tougher one.
Although, another side of the coin, there is known issues with the camshaft position sensor on these engines. It is a combination of a camshaft position sensor with a synchronizer ring assembly. Normally when it goes or it's way south, it will chirp/squeal making it sound like a bad pulley, along with engine roughness in all ranges -- not just idle. But you should get a service light.
At the end of the day, you shouldn't be getting any backfires. Which is why I am leaning towards a timing issue.
Although, you can take it to Ford, they can run a diagnostic on it, and it's a 50/50 chance they will find something wrong. I want to say drive it until it gives a code instead of wasting time changing out electronics and the such.