Engine/Transmission (1998.5 - 2002) Engine rattle!

[Mbranson]

Recently I have noticed a engine rattle when I accelerate! This normally occurs when the motor is at operating temp while I'm driving on the freeway for a while.It sounds like pre ignition rattle that a gas motor would make as if it had bad fuel! I have had many tanks of fuel through it from different stations, so I don't think its a fuel problem!Truck has no running issues,runs just like it always has! Would love to figure this out! Thanks in advance!!! Mileage 80.000

01.5, auto, 4x4, 2500, longbed, Ispro, pyro, boost, fuel gauges ,FASS 95 GPH lift pump, Motor completely stock, Intake stock, Exhaust stock, Cummins.

 

[JR]

Check valve lash

 

[SAndreasen]

Check valves maybe run a couple bottles injector cleaner through it . I use a little engine oil and power service in every tank sometimes even some atf but don't tell anybody as likely one day the world will reverse rotation if you keep using atf.

 

[JR]

The world won't change rotation but its a good way to get rid of that pesky injection pump and hog out those tight injector nozzles and pack that oil full of wear metals, zinc and sulphur those lousy lube engineers forgot to add.

 

[Vaughn MacKenzie]

It could be your intake air sensor is off (IAT sensor) and causing your ECM to think it's colder than it actually is and therefore it dials up more timing advance. The system increases timing when cold for better emissions which causes more rattle.

I have had 4 24-valves over the years and most of them when I'm lightly letting off the throttle at just the right spot I get a lot of rattle for a moment, especially on the two I had that were manual transmission. I think the programming of the ECM advances timing more at light throttle to improve fuel economy.