Douglas Carpenter

I took my Express 1500 (2000) conversion van to the mechanic (5.7l engine) because it hesitates when it is cold and then runs ok. They said the distributor was bad and charged me over $600 to replace the distributor. I took it back the next day because the service engine soon light was coming on. I get it home tonight and it still hesitates. Vacuum leak?

I have another problem also. 2 years ago the oil pressure gauge started dropping to zero pressure when idling. It would kick on the check gauges light. They claim they replaced the oil pressure switch. It would show about 40 psi when cold and drop down to a steady 20 after that. Took it back again twice this week and they claim they fixed it but it still does it. Now they say they think it is the oil pump. Thoughts?

canucklehead

My engine on my 2002 did that. Turns out the oil cooler lines were leaking enough, plus the thin crap oil they make these days that I was actually losing over 2 litres between fills. Also at idel my pressure gauge would go down right to the top of the red line.
I fixed this my switching to high mileage oil.
Read up on ZDDP and what it does when added to oil. New cars have tighter emissions systems and the zddp was damaging them, so at the expense of our engines they reduced the zddp in oil to compensate for the emissions system wear.
Crap right?
High mileage oil has higher levels of zddp, and after switching I show higher oil pressure at idle and at cruise as well. I also show a litre less oil loss over the 5000kms.
Its not a perfect fix, but 5 w 30 conventional or even synthetic is not good enough anymore.