Engine/Transmission (1994 - 1998) Engine sounds like it's running on 5 cyls.

[mdivincentis]

Okay guys,

My truck has been running a little rough lately. Definitely low on power, too. Also, seems to smoke more under boost. Best way I can describe it is it sounds like the thing is running on 5 cylinders. It has been like this since a brief trip to 4000 RPM without HD valve springs. Don't ask why or how .

So, what items are usually damaged when I pull a stunt like that?



Truck details:

'98 12v NV4500, 0 Plate, 370's, HX35/40-16, 4K Gov Springs.





Thanks,

Matt

 

[Lsfarm]

Overrev

Well you may have bent valves, bent pushrods, dented piston crowns, or all the above.



Disconnect your fuel shutoff solenoid so the truck won't start, and crank the engine over. Does it sound like it revs up on one or two cylinders as it cranks?? If so you have low compression on a few cylinders from the damage.



You're probably going to have to pull the head, and get some work done on it.



Or you may be lucky and find only bent pushrods which aren't opening the valves enough, causing the miss, and just a few new pushrods and a valve adjustment and you'll be back on the road



How's your luck??



Hope it it the easy fix. Greg L