Lately my 93 v8 has been sounding a little strange. It's always sounded like this when I first start it up while it's still cold until I drive it for a mile or two. It's difficult to describe it, but the engine sounds almost like it's straining while accelerating, and I can literally hear it go back to normal and smooth out while I'm going down the road. It's always sounded like this after I first start it up, but gone away after a few minutes of driving, but lately now that the heat has started here in Texas, I've noticed that not only does it do it in the morning when I leave the house, but also if it's warmed up to normal operating temperature and I've sat at idle for a minute or so like at stop lights. Pretty much every time I stop at a red light it will begin to do it again until I give it the gas and accelerate pretty good and then it evens out again. I recently changed the plugs, wires, tps, iacv, fuel pump, oil pump, fan clutch, t-stat, radiator cap, distributor cap/rotor and did an oil change. I've got no check engine lights whatsoever, and the engine temp never really gets over the 1/2 way mark in the dash gauge. It's got about 212,000 miles on it so I don't anticipate it will be alive much longer, but it's my only means of transportation for the time being so I'd like to do something about it if possible to extend the life as much as possible. Does anybody have any idea what I'm talking about lol?

 

Sorry its hard to diagnose a sound unless its in person. The best suggestion I can give is to find the location of the noise. Have someone drive the truck while you poke your head around the cab and listen to see if it is in the engine bay or under the truck or sit in the bed and listen maybe it is the rear-end. Maybe have someone drive your truck while you drive next to it in another vehicle. Good luck.

 

It appears to be coming from under the hood and not from underneath the truck or the rear. I'm pretty sure it's the sound of the engine itself. It can be heard while the truck is in park and not moving if you give it a little gas. The sound of the entire engine changes. Normally it sounds low pitched and you can hear it firing, but when it changes it sounds much higher pitched (almost like a whine) and it feels like the power is much lower and it's struggling. You can literally hear it change back to normal while you are driving down the road if you accelerate for a little while. Oil pressure is reading normal and the temp looks okay, too.

Also, recently it's begun shaking a little bit while in drive at the lower end of the 1000's rpms and I had it stall out on me this morning on my way out of the apartment complex. The past few days it just feels like it's running much more roughly than it used to and at a stop it will sometimes idle very slow and/or erratically. I haven't gotten even a single check engine light through all of this.

 

Valley pan leak? It's a common problem on older V8's and isn't too bad to do. Check out Hughes replacement or do an Ebay search--there's been a guy selling replacement pans there.

Only 212000 miles?, barely broken in!!! Mine has 230,000 and I expect to have it for at least another 5 years. Relatively cheap driving, no payments, no expensive full coverage insurance, what more could I want? When it needs a new engine, I'm gonna do it.

 

Y'know what? It actually sounds like you're describing the fan clutch kicking in... Right when it starts up and then when it's hot, and it makes it feel more sluggish... and it makes a roaring/howling sound? That's a perfect description of a viscous fan clutch doing exactly what it's supposed to do.