Rough Idle
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Freshman User
Joined: Sep 2009
Posts: 36
Likes: 0
From: Novi, MI
Rough Idle
About the Truck
95 F150 300 I6/5 speed
Recently did a tune up
Plugs, cap, rotor, plug wires
170k miles
The truck was running a little rough when I bought it, so I did the tune it. It seemed to help, but still wasn't running as good as I wanted it too. I did a massive amount of research on the EGR restrictor plate mod. So I made and installed a plate, drilled an 1/8" hole in it, sandwiched it between 2 new gaskets using high temp RTV, and it completely cured all of the off idle stumbling and chugging I had. But I'm still not satisfied with the idle. It sounds almost like a miss, but I'm not convinced it is. It's not to the point of completely stalling by any means, but it's a rough idle none the less. It doesn't matter if ithe engine is warm or cold, it does it all the time but seems worse when it's extremely cold outside. It drives beautifully, but this idle thing is bugging me. Does anybody have any thoughts? I was thinking maybe the IAC? The CEL hasn't come on at all since I've owned it. (I know it works though) Any suggestions?
Thanks
95 F150 300 I6/5 speed
Recently did a tune up
Plugs, cap, rotor, plug wires
170k miles
The truck was running a little rough when I bought it, so I did the tune it. It seemed to help, but still wasn't running as good as I wanted it too. I did a massive amount of research on the EGR restrictor plate mod. So I made and installed a plate, drilled an 1/8" hole in it, sandwiched it between 2 new gaskets using high temp RTV, and it completely cured all of the off idle stumbling and chugging I had. But I'm still not satisfied with the idle. It sounds almost like a miss, but I'm not convinced it is. It's not to the point of completely stalling by any means, but it's a rough idle none the less. It doesn't matter if ithe engine is warm or cold, it does it all the time but seems worse when it's extremely cold outside. It drives beautifully, but this idle thing is bugging me. Does anybody have any thoughts? I was thinking maybe the IAC? The CEL hasn't come on at all since I've owned it. (I know it works though) Any suggestions?
Thanks
Post Fiend
Joined: Mar 2002
Posts: 19,402
Likes: 38
From: Bonita Springs FL
I had a rough idle like what you're describing too. I did the EGR fix and it helped but it wasn't completely better. After checking a bunch of things I finally discovered that when I'd done the tune-up one of the plug electrodes was bent and that cylinder had been misfiring the whole time. Re-gapped the plug and it idled smooth.
