I am having a couple issues with my 460, probably related. The first is most noticeable driving in traffic - it seems to cut off/on at around 2000 rpm's. When letting off the gas, it goes smoothly till 2000 then drops off suddenly, opposite going up. It feels like the EFI cuts off/on instead of flowing smoothly. The other issue is a miss when accelerating hard or when pulling hard with a load. Again, it feels like the fuel injection is just not right. But, maybe I'm way off and it's ignition. Any suggestions? I was headed out now to put in a new oxygen sensor but just learned in another post that there may be more than one sensor. True?
Thanks.

 

It may be the ignition control modual going whacko

 

You have two 460s listed -- is it the 93 or 97 and have you scanned for any codes? I also happened to notice you lived in Aspen CO. Trucks operating in these higher elevations come with their own set of peculiar problems normally and when sensors start failing. First, however, is scanning for diagnostic codes.

 

Oops, I'll go fix my signature. The '97 is the 460, the '93 is a diesel. I haven't scanned for codes because the only scanner I have is OBDII. I never got around to buying one for these trucks but I guess it's time to spend the money. Which port does the scanner plug into? There are 2 right next to each other under the hood near the brake booster.

 

Code reader ordered…

 

Sounds like a fuel problem. Put a gauge on it and I bet the fuel pressure drops below 30psi @ 2000 RPM.

 

Thank you for helping me with the year (1997) and that code reader will serve you not just now but in the future. I agree with subford's comments about it possibly being a fuel problem but we'll have to do this methodically and see what the EEC is telling us too. Have you ever performed a fuel pressure test and are you familiar with the procedure?

 

Both plugs get plugged in to the code reader.

 

I've never had an OBDI reader but I use my OBDII all the time. I've also never needed to run a fuel pressure test. I bought a guage but have never used one before. I looked it up on this forum and was ready to do it today but got rained out. I'm pretty familiar with this motor - I installed the long block myself about a year ago so I had everything apart and back together. The 2000 rpm problem was there on the old motor too. I never dealt it because I was too busy working and being a Dad to worry about it. Now that it has started to lose power and miss on acceleration I can't ignore it any longer.
Thanks for the help