My truck recently experienced a really bad and shaking idle. The rpms dropped below 500 and then they where fluctuating up and down. No check engine light occurred and once I hit the gas a little it smoothed out. I also noticed the truck had a slight buck on the highway and then the shaking at idle occurs once I got off the highway. I just recently replaced all timing components beside the vct solenoids. The idle felt exactly like my friends truck did with the bad solenoids. Any ideas what it could be?

 

I've been battling the same issue. Perhaps vacuum leak? Coil or injector bad? I'm not sure...Chasing the answer myself

 

We'll when I was driving today the check engine light started flashing so I'm dealing with a misfire. Maybe a coil that is going bad. Maybe that is the cause of the rough idle?

 

That would do it. I replaced one coil and the problem is still there, so can't say for sure

 

I was also planning on cleaning my throttle body and maf. Also I was planning on replacing the vct solenoids.

 

Umm yeah.. a flashing CEL is telling you mis-fire ! How many miles on your motor ? May be time for a tune-up.. along with what you mentioned above.

 

Change ALL the boots and springs. Check the coils with a multimeter. Coils don't go bad very often. Most people buy new coils when they don't need to. Check out this video.

 

Also there are SOOOOOO many threads on this. Use the search function and you will find many things to try. I still suggest you start with changing boots and springs.

 

I have 92k on it and I have already changed all the plugs. I'll be plugging in a ford ids to see which cylinder is misfiring.

 

I would just say do ALL the boots and springs! If one is bad the others are probably due as well.