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'93 Fords will have an oil pressure switch, so yes, jumping needle would indicate wire or switch issue.sorry to hijack, but Ron I have a hydraulic lifter sticking in the 93 4.0 ibelieve. But my oil pressure gauge shows pretty good pressure til i drive and then bounces around real bad, i figured bad sending unit. but i have ALOT of miles. any thoughts?
Thanks I will give atf a shot and see what it does.You could be correct. But you may not. And for a few dollars he will able to see if the lifters are ticking because they are bleeding down. If that does nothing, then there could be mechanical damage. I taught Autoshop for years, over 20. I certainly know what goes on within an engine. And if he has worn parts, then this won't help. But gummed up lifters is a common occurrence with engines that have the camshaft in the block. ATF has solved this problem too many times to count. So let' give it a try. It's certainly not a poor decision to try it. I'm not suggesting any additive to quiet it down, I'm talking about removing varnish from within a hydraulic lifter. Have you even taken one apart? I used to have an example mounted on the wall that I took apart so students could see the internal workings; not much there really But enough to get gummed up easily.