So, for the last week I have been hauling broken concrete to the dump (carport parking pad in way of garage build). A load or two after work averaging 2500 lbs - 3000 lbs each. This morning my brother came over and we carried 3 loads at 3200 - 3400 lbs each. Overweight I know, but it's only a few miles to the dump and I'm working against a clock. Dump is only open until noon on Saturday. On the third load the RPMs went up around 1500 to get it moving and barely wanted to move. Accelerating down the road it was missing/breaking up pretty bad, when I got above 1500 RPMS it would make a dieseling noise and the RPMS would drop to 1000 and jump back up to 1500. It did that until it shifted into the next gear, and would do it again until I was up to speed. Unloaded that load and it drove like normal going home. Bit of a stumble off idle, barely noticeable, but otherwise drove normal. The next 3 loads we loaded at 1700 lbs each and the truck handled it much better.

I bought the truck last month and have been working it like a mule. It has been handling it well. I haven't done much in the way of maintenance. Replaced most of the vacuum lines because they were rotten. Changed the oil. Otherwise nothing. The plug wires look crusty, plan to do plugs, wires, cap and rotor. Air filter is a K&N and is filthy, have a recharge kit, will clean it. Any other areas to look at?

Also, have been having issues with the trans shifting hard at times. Intermittently. Throws a code 451 (IIRC) - VSS signal. Haven't done anything to troubleshoot the issue. It's very random and seldomly does it. Not sure if that is related to my run issues today.

The only reason I have neglected the truck to this point is I have no garage. Just bought the house, it has no garage, I am in process of building a garage. I HATE working in the driveway. All of my tools are packed away in the shed or attic. I am trying to do the minimum to maintain the vehicles until I get the garage built. This fall I hope to have it done and will go through the truck with a fine tooth comb.

 

The efi 460's are bulletproof. Plugs and wires are a good idea, I'd trash the K&N in favor of the oem filter. The speed sensor is in the rear axle on that truck. Check the plug, check the sensor.

 

The speed sensor is probably telling the computer that the truck is moving faster than it actually is, so it is in a higher gear than it is supposed to be, and when you start off, it's lugging the engine. That's your stumbling and dieseling noise and trouble getting above 1500 RPM.

X2 on ditching the K&N, they just don't filter very well.

 

I figured the VSS sensor and this lack of power issue were not related. You guys think it is? Guess I'll have to crawl under the old girl. Did I mention I HATE working in the driveway?