2000 laredo 0 oil pressure on idle goes up to 40 while driven?

(2011-11-07 15:20:07) 1. MercadesCage Says: A day ago I heard my engine start to whistle, this whistle would go high pitched then fade out as I accelerated to 2500 rpm then this morning while driving it oil pressure stayed at 0 on idle and came back to 40 while accelerating. No knocking or out of the ordinary engine noises happen during this process. I'm nervous to drive it as I've been told it could be a weak oil pump. I've bought a oil pressure sending unit but half not put the part on yet as it was 40 bucks and non returnable. Any ideas? It is the straight six if that helps.2. Blair Says: It sounds to me that you developed a vacuum leak and that would make the whistle you are hearing . Now for the oil situation i would put in the new oil sending unit as they had a high failure rate . I assume your oil level is correct . Then when you find you have oil pressure at idle it will put your mind at ease .3. bandit_60 Says: yes it could be a weak oil pump or the sending unit. i figure it,s the sending unit. Tag: 2000 laredo 0 oil pressure on idle goes up to 40 while driven?