I have a 2001 Ranger V6 3.0 with AC. It has a pretty solid misfire sometimes that I feel most when I am in drive with the brake on. Happens more when the AC is on, and not just when the compressor kicks on and off. Replaced the coil pack about a year ago. Check engine light comes on for a week, then off for a week. I'm pretty mechaincally enclined, but damn these newer engines.

I had a similar problem, Id check the synchronizer unit towards the rear of the engine (where the distributor is usually located).

I also had the same problem but i screwed in some bosh platinum plus spark plugs and i've been running good sense. might give it a try...

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Ranger's rule!

had the same problem too and also went with the platinums but that didnt work so i got new plug wires and that fixed me right up.

I noticed it only does it with the AC on

Take it to Autozone and have them pull your codes for free. Come back with the results. The best way to diagnose these newer computer systems is to read what it's trying to tell you. And mostly the codes won't point to a specific sensor in general, but that it sees something out of range that might be caused by an entirely different part of the sytem. And as stated, if the engine hasn't been tuned up (plugs/wire), do so now to elimnate that as a possibility. But I only reccomend OE plugs, 3.0Ls are funny about what plugs you use.

Pete

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1993 Ford Tempo 2.3L OHV HSC Auto - D/D Stock.
1988 Ford Ranger - 5.0L AOD Swap.
2002 Dodge Caravan - 3.3L Auto

Autozone no longer offers that as a free service. One lady misdiagnosed her vehicle and sued Autozone. Screwed us all. My buddy has a Code Grabber but it's lent out. Will find out soon enough.