1998 Ford F150 Oil pressure Problems

1998 FORD F-150
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UTCLAWMAN
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Engine Performance problem
1998 Ford F150 6 cyl Two Wheel Drive Automatic

I have a 1998 Ford F-150 with 155,000 miles. When I fist start and run my truck, the oil pressure is fine.. After about 15 to 20 minutes of driving, my oil pressure starts to flucuate, but only at idle,in gear at a stop... The longer I drive the lower it gets. Final to were it reads nothing on the dash gauge.. As long as I am on the gas, or in park, the pressure is fine. Is this an oil pump problem, or bearing problem?.. I can hear the lifters rattle, slightly.
Jun 11, 2009 at 8:53 AM
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RACEFAN966
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FIrst off before figuring on the worst have you changed the oil pressure sending unit to see if it is faulty or not? As for the oil pressure as you discribe it sounds more like a cam bearing problem. With cam bearing oil pressure is good cold and gets lower as the oil warms up. This is caused from lack of oil changes or weak oil pump. So first change the oil pressure sending unit if that don't help then get back to me and we will go from there.
Jun 11, 2009 at 10:31 AM
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UTCLAWMAN
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What is a new cam and bearing gonna set me back? Ballpark??
Jun 11, 2009 at 11:52 AM
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UTCLAWMAN
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Could it also be a rear main bearing? If I only loose pressure when in gear, at a stop?
Jun 11, 2009 at 2:50 PM
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RACEFAN966
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Well you should rebuild the motor to do it right but like I said before jumping to the worst replace the oil sending unit if that don't change it then get a manual oil pressure guage and see what oil pressure really is. Let me know what you find with that first and go from there.
Jun 12, 2009 at 8:43 AM
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