I took a short trip, about 500 miles, to see if my recent work did any good. Not sure, but early signs aren't promising.

The truck still has a studder/stumble as it's slowing to an idle, like when you come to a slow stop, and again, when you pull away from that stop, for the first couple of hundred rpms from idle. I don't feel it while driving, but I'm not sure because, now, I think all the vibration I feel at freeway speeds is from my tire/suspension. When I got the truck, the driver's side shock was just flopping around in it's mounting hole, no nuts, bushings or anything. The tire on that wheel would wear out fast, with scalloped,m uneven wear. I replaced the shock, but a parts house gave me one with only one bushing and one steel washer. Seemed weird, but it was a sealed package, so I installed it, with the bushing and washer on the top. That tire is still wearing out, and I can feel it bouncing, and making weird noises, more at freeway speeds.

I'm also thinking the bearings are worn out - I hear some roaring at times. I'm thinking front bearings on an F450 won't be fun; probably too big for my tools.

Back to the engine stumble...When Razzi plugged it into IDS, he said #6 injector was weak. Is that something that would cause a consistent stumble like that?

Recall that I replaced the water pump and back-flushed the oil cooler and deleted the EGR. Granted, the weather was chilly, so I'd expect the truck to run cooler Still, I thought 190 degree ECT was pretty low. It never got much above that. Typical ECTs have been in the low to mid-200s. More importantly, the delta was not a lot different,12-15 degrees, although it was more often 12, when it used to be 15 most of the time, and sometimes up to 17 degrees. Again, not sure if that's just from the cooler weather as well.

 

Jack the front end up and try to move/shake the tire back and forth and if there is any play the bearings are shot. I just had both front hub bearings crap out at the same time and just replaced the whole hub on both sides. Is yours 4wd?

 

No, just 2WD, but I think these 450 hubs are bigger and heavier. The removal/install process may be different. I didn't see a YouTube with a quick search, but I'm going to try again. Dang, just shaking these 19.5s with steel dually wheels ain't easy. It may just be the bad tire making all the noise. Step one, another shock. Step two, tire, then bearing.

 

My 2006 now has a very healthy oil cooler and fairly new factory thermostat. It runs ECT right at 190 deg. when it's 40 deg. air temperature. The EOT is usually 3-5 degrees higher at 65 mph. That spread is fairly consistent in warmer weather but based off ECT of 195-200 deg., depending on temperature outside.

A failed thermostat was resulting in ECT never rising above 160 deg in winter. That 30 degrees makes all the difference. It is hard to get the cab heated when the temp is 155-160 and it's well below freezing outside. Truck doesn't run well either.