2004 1500 5.3 low oil pressure after using Lucas engine stop leak. No pressure at idle just below 40 when driving. Replace the sending unit and pressure improved for about a day. Just had a manual pressure gauge hooked up and it shows the same as cluster. No engine noise at all. I was informed that using Seafoam or another solvent could loosen up build up and cause damage. Trying to find out if using an engine flush machine may help. I am assuming that the cause of the low oil pressure is due to build up from using several qt of the stop leak over a four months. Please advise.