1996 Oldsmobile Cutlass lifter knock?

VMHAWKE

MEMBER
1996 OLDSMOBILE CUTLASS
6 CYL
FWD
AUTOMATIC
149,000 MILES

Hi. Here's the thing, my 96 olds 3.1 has what I figure is lifter knocking. The weird thing is that under normal driving, the knocking all but disappears. At around 50 - 60mph, the car sputters like there is a drop of water in the fuel. I can let of the gas and then push it again and the car runs smooth for a few seconds before bogging down again. I can also floor the gas pedal to the passing gear and it will run fine for a few seconds before it starts sputtering slightly again. The whole time it sputters, the knocking becomes loud again, but as soon as the car smooths out the knocking subsides. I have given the car a complete tune-up, including changing the fuel filter, and have put a couple cans of SeaFoam thru the tank and into the oil as well, but nothing is helping. I am at a complete loss here and cant think of what could be the problem. Could you plese help? Thanks for everything.

4 Replies

RASMATAZ

MECHANIC
75,992 POSTS

You sure the knocking noise is not detonation/pinging instead of lifter knocking-

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Saturday, March 1st, 2008 AT 7:15 PM

VMHAWKE

MEMBER
3 POSTS

Hi there, yes it is a definately pronounced knocking. From where I can tell, the knocking is coming from around the front valve lifters on the far left side of the engine. I checked everywhere around the motor with a mechanic's stethascope as well as with a screwdriver(it still works lol), and that is the only place where the knocking is heard the loudest. I figured it is a collapsed lifter, but I wanted to know if anyone had any other opinions before I decided to tear into it. Oh, I forgot to mention earlier that the car has had this knocking for over 3 years, after an apparent lifter job from a shadetree, with no affects to the drivability of the car at all til now. I have only had the car for 3 months, and it has been very reliable aside from the noise. I had to replace the fuel filter and tune-up the car only because it started the studdering and power loss upon acceleration. Thanks again for all your help and advice.