Hi all,

I bought a 2001 Ford Ranger last May. The truck ran great up until last month. Everyonce in a while I would feel the truck pull down and as it did I would watch the tacometer... it would fluctuate up and down between 300 to 800 rpm over and over. Didnt think too much of it, but then it progressively got worse. It only did it when the truck was idle, either in park or when I would come to a complete stop. It got to the point where it would do this just about every time it was in an idle, and when it did it, It felt like the truck was going to die, but then it came back to life (i know that is a very lame description but whatever).

This goes on for about a month... Then, my AC stops blowing cold air. This is when I finally decide to take it to a mechanic. He tells me that there is an O ring on the back side of the compresser that is leaking fre-on. I say okay, fix it... I drive it for 5 days and take it back to the mechanic (upon request) and he checks for leaks. Turns out, the compresser has a bad leak too. He also tells me that the reason my truck is running so rough is because the clutch on the compresser is going bad.

So I have the compresser replaced. I get in my truck after the new compresser has been installed and it runs like a dream, at first... I drove it home that night and parked it in my driveway. I decided to just let it sit there idling... After a while, this compresser would do the exact same thing as the old one, just not as bad... but still noticable and the rpms would fluctuate as well (again not as bad).. After the clutch disengages it then re-engages... when it re-engages is when I get to see the motor pull down and shake, and then the clutch will disengage again and then re-engage. This cycle happens around 10-15 times until finally it starts spinning coninuously. This is what the bad compresser did, but it did it constantly. The new one will do it after about 5-10 minutes of idle, then the compresser starts its cycle of engages and disengages and then the truck runs a little smoother. It feels as if the motor is struggling to spin the clutch back up...

So I decide to turn the AC off, and then back on to Max AC... when I do, the clutch on the compresser will disengage, when I turn the AC back on it will of course re-engage. However, when it re-engages when I tell it to, it does not pull the motor down, the rpms do not fluctuate at all, and the truck never misses a beat. This here, is the reason why I am worried. Why does the clutch on the compresser cause the motor to pull down on its own, but when I turn on and off the AC it doesnt pull it down at all? Its a new compresser... I looked at it and it still has a shinny coat of black paint...

Now. I am a computer technician, not a mechanic and I dont know jack about motors. But this doesnt seem normal to me. Maybe Im just paranoid, but I thought I would ask some of you Ranger enthusiusts!

The mechanic asked me to bring it back in another 5 days just to make sure everything is working as it should. I trust the guy, and I dont think he would try and screw me over, but I thought I would get some second oppinions.

Thanks in advance to all who reply.
-Neil