Engine load

Still completely stumped. Have been fighting a dragging issue for a couple weeks now poor mileage even on down grades. Both front calipers were replaced under warranty for slightly dragging. If I pull up the engine load PID on my EzLynk cruising unloaded on the highway (70) it’s around 65 to 73 percent pulling about 2.5 to 4 degrees on timing slight increase in grade and it will go up to 80. I’ve seen others crusing with the load percent significantly lower. Alignment is solid, tire pressures are perfect, fuel additive every fill up, same station usually. Fuel filters and air filter changed as well.

jack the truck up and spin each wheel by hand.
pop the serpentine belt off and spin each idler and accessory by hand.
watch ebp and see if it is acting erratic causing the vgt to respond inappropriately.
with it in 2wd and hubs unlocked, spin the front driveshaft to see if there is a u-joint binding. For the rear, get under the truck after a drive and feel how warm the u-joints are, if you cant touch them or the grease is smoking, you have an issue.
Change tuning for a tank and see if anything changes?

Occasionally the slides on the rear calipers freeze up due to corrosion.


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PowerStrokePops said:

Occasionally the slides on the rear calipers freeze up due to corrosion.


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quick way to tell is with an infrared thermometer after a drive. Compare temps on all four calipers.

Where are ya located? Seen plenty of rusty parking brakes cause issues, which would be found with sooties suggestion. Also, see if the ac compressor can be turned, grab the cluch, and it should spin, albeit with some resistance. Also, with the belt off while doing what sootie said, check the ac pulley, it should spin freely with no power to the clutch.

Does it make any funny noises while cruising? Like maybe a diff bearing starting to go/freeze?

Spent the day checking most of the easy stuff and monitoring PIDs. (Stock tuning currently.) U joints are cool to the touch after an hour drive. Front calipers were warm but nothing like they were before. Rears were cool to the touch. Front wheels spin free lock to lock. Checked axle shaft joints and no signs of binding. Greased them as well. Can hear rusty dragging noise from rear axle assuming parking brake. Exhaust back pressure was about double the boost pressure, didn't jump around. Vane position at cruise was usually between 29% and 42%. While cruising and coming up to any situation that required any more power you feel a groan almost like the motor is under heavy load which is usually around 75-85% load according to Ezlynk. I did however notice the same time my mileage dropped my boost pressure at cruise is higher and very responsive and the motor is very clatterly, just barely getting on the throttle will make 6-8 psi quickly. Before maybe 2-3 psi but also had a day were I could barely make any boost and felt like I had no power, thought it was a bad batch of fuel and haven't seen it again. Truck will hold 6th till the absolute last minute around 750-800 rpms and harsh down shift to 5th. Playing around I turned the exhaust brake on and load stayed under 55 % no matter the situation and timing stayed under 3.0 degrees but shuddered when locked up??? Tech at local dealer said it could be coming from the transmission any thoughts?.

Check engine and trans temp sensors. Seems like it show up somewhere obvious but sounds to me almost like it is thinking things might be cold.

Will do. About a month ago driving down the highway on a down grade unloaded 60 mph on cruise the trans kicked me down to 4th and wouldn't up shift until I pulled over and cycled the key once. Never happened again so I didn't think twice until now.

Verified both axles this weekend nothing causing a drag. So its either coming from the motor or trans. I did have an issue with number 8 injector in may 2016. Dealer performed a manual power balance per TSB and reset fuel tables and reprogrammed the pcm for the new *** regeneration TSB. Since then the truck was never the same. Is it possible it just learned a bad habit and a reset, may be the be all end all? Just a shot in the dark but an unloaded truck shouldn't be at 80% load on the highway and it just makes driving not enjoyable.


Thanks in advance.

Is it worth disconnecting the batteries for about 10 minutes with the headlights on? This should reset some/all of the adaptive memories. May help :shrug: