Hello everyone, here's the deal. I have a 1995 manual 12v that's been a great truck. It's never had any major issues and I try to do all the necessary preventive maintenance, etc. A couple weeks ago I was leaving for class and had to accelerate fairly quickly to match the pace of the traffic and make the on-ramp; nothing crazy. Well this particular day I went for a small window in the traffic and probably revved a little too much. Now I know my truck has a limiter on it because the guy at the dealership showed me how it worked back in 1999 when I bought the thing. Ever since then I've never had to see it in action, but this hard acceleration in 2nd gear pushed the RPM until the limiter stopped it. I was looking back over my shoulder at the time and not at the tachometer so I'm not sure what RPM I actually went to. When this happened it felt like I immediately lost power and the truck lurched forward. Afterwords, everything seemed normal...until last night.

I was on a freeway coming home and was doing about 60mph. I wanted to accelerate up to 70 but my tachometer wouldn't go up past 2000rpm, even with the pedal to the floorboard, and I can't go faster than about 68mph. Every gear seems to stop me at 2000rpm now; I could've sworn the limiter happens just before I red line (ie. much higher rpms than I get now).

I should note that when I first had the truck in 1999 it seemed a lot quicker, both in acceleration and response. As the years have gone by it's seemed slower and slower. I can start moving from a stop but there's a point where it doesn't matter how much I mash my foot on the pedal, my truck just leisurely accelerates. Can anyone point me in the right direction as to why this is happening or what the problem may be? Thanks for the help!

(oh, and I'm kinda new to the Houston area so if anyone knows of a great mechanic that knows their diesels I would be extremely grateful!)

 

Check to see if you are getting full travel on your throttle lever on the pump. That would account for the low rpm and low power. There is a governor on these, but they begin to defuel around 23-2400 rpm, and will limit total rpm to around 3000 or so. At 2000, you should still have full power. Not sure on the 95's, but both of my trucks have a threaded rod that has a left and right hand thread that will adjust the length of the linkage rod. If it lengthens, then you will get less throttle even when the pedal is to the floor. This happened to me a couple years ago.

Do you have gauges in the truck? Boost and EGT would be good to know.

 

I would suspect low fuel pressure.
Has the prefilter ever been serviced or the overflow valve replaced?

 

This is one of the best shops in Texas, if not THE best.

http://www.hotroddiesels.com/

I by passed by a pretty good one in Buda while on the way to Hitchcock.

 

Thanks for the thoughts, everyone. My knowledge is limited with some of this stuff so if it involves looking outside of a Chilton I'm probably going to be lost. I will look into that shop you told me about GAmes and relay some of the things y'all said might be the problem. I'm just afraid this one is beyond me. I'll keep this updated when I know more.