My parents own a 1991 Plymouth Grand Voyager SE with a 3.3 V6 engine and a 4-speed automatic transmission.
When they were taking some big stuff over to a store for refunds, they ran into a couple of problems with the van.
1st: During the day, the van was running fine at first. But when my parents accelerated from a stop from a red light after getting on a busy major road, the van started exhibiting a strange behavior after getting into 3rd gear at 35 MPH. It stopped picking up speed even when he floored it. Despite that, it then started to lose speed and then went to 0 MPH. The engine cut out and stalled. He put the shifter to "N" mode and restarted the engine. He tried to accelerate again but it wouldn't hardly go and cut out again when applying pedal pressure. Again, put it in "N" and restarted it. Instead, he slowly gave it pedal pressure and managed to get to a parking lot. He parked it and checked underhood.2nd: The next problem. The oil pressure gauge was showing 'nil'. Basically, it was showing no oil pressure. They said this happened all day while they were driving.
Before the two scenarios occured:
--I drove the van over Christmas week because I had to borrow it due to some wheel bearing repairs that had to be made to my '91 Plymouth Sundance RS. While driving it, oil pressure was ok (almost 1/2 driving and 1/4 hot idle) and no drivability problems.
--I checked the fluids while I put gas in like my dad asked me to. The oil level was full, though it looked kinda old, 'dark' brown and kinda blackish. My dad uses 10w-40 oil in this engine based on the oil bottles I saw in the van.
--The coolant, on the other hand, was pretty low. The overflow tank was way down and appeared to have tap water. The radiator? I could see almost nothing in it. I took about 1 gallon of 50/50 antifreeze and water mix to bring everything back up to level. The engine never ran above normal or anything nor did the temp gauge swing. My dad told me that the van was bad on coolant loss but didn't notice visual leaks.
Anyway, my parents got the van towed that day to a mechanic and it's currently getting checked right now. They told them to change the oil, run oil treatment, and check the true oil pressure with an actual gauge. As far as the drivability problems, they want them to hook a scanner to the van and drive it around, but they want the oil pressure thing rectified first.
What's going on? What could be causing the above scenarios? Thanks.