First off, I've got a major loss in power. I can get no more than 60mpg on flat ground. Second of all, when I try to floor it, it seems to kick down into a lower gear, wind up, and go slower. Third of all, I get this odd clunking sound at low speeds...mostly first gear. Possibly the tranny or something else?
Hey Biz, all the members of this board will need a little info about your truck to help!
Like, what year, what engine, carb or Fuel Injected?
Also a help (I think you meant 60MPH, not MPG!), what happens at 60? Does it buck and miss bad, or does it run smooth, but no faster?
Biz......did you happen to have any damage to the exhaust recently? I had this happen to me on an Econoline van that I had a few years ago. I'd backed into something solid......didn't think much of it. I took a trip to New England that night and I couldn't maintain 60 in a head wind. I had to put so much throttle to it that it would kick down into second.......reach 60 or so and shift back into third...........where it would slow below the kick down limit and on and on. I finally solved it by drafting an 18 wheeler. When I got to Mass. I looked at the back of the van and found that what ever I backed into had crushed my tail pipe outlet about 3/4 closed.
If you don't have a damaged exhaust I'd look (well check out) the internals of your cat or muffler for baffles that have broken loose and are restricting the flow.
If your saying that the pavement turns to wet cement at 60 but runs okay at the lower speeds and exhaust restriction would be the first cause that comes to mind. This could also explain the noises that you hear.
Figures don't lie ....... but liars sure do figure.
Things i'd check. The exhaust system is a good idea, i've had a cat converter go on me before also.
Are the spark plug wires in good shape?
Try unplugging the exhaust oxygen sensor, if the problem goes away your o2 sensor is bad.
How old are your fuel and air filters?
spark plug wires perfect...just recently replaced. Air filter is okay, but I need to check the fuel filter. I'll check the exhaust system sometime tomorrow. Thanks for the help. I'll post if the problems continue.