1998 astro stalling issue, engine codes

[dougzooka]

Hello, this is my first post on the forum.

I just bought a high mileage (380,000km) astro van last week.

The van seemed to be running alright when I paid for it. About 4 blocks on my way home with it, the van stalled when trying to accelerate from a stoplight. It would not start again. I stalled next to a gas station, so I tried putting more gas in incase the fuel had gone bad. The van started right up.

I made it home, 1 hour drive time. The van would hesitate and try to die everytime I stopped at a light. The only way to keep it from dying was to accelerate pretty hard through it sputtering. The last 15 minutes of the drive it was hardly wanting to die when I accelerated.

Put an obd reader on it. Codes p0102, p0300, and p0420(this code came up twice).

I cleaned the MAF sensor with sensor cleaner. Started van, seemed like hesitation was completely gone. Thought it was good to go. Checked again yesterday. Hesitation/stalling is back.

Tried cleaning MAF sensor again today. This time made no difference.

Does changing the MAF sensor seem like a good starting point here?

EDIT: some extra info. The van seems to idle okay. It's only when I try to apply the accelerator that it will die. If I put the throttle on enough, it seems to power through stalling and runs fine at higher rpms. When it dies, it will not start again right away. If I wait about 15 minutes, it will start again with no issue. The guy I bought it from said the van runs cold, and it seemed like it didnt heat up much on the hour long drive. Stuck open thermostat maybe? The oil pressure gauge jumps around a little as well. Changed fuel filter, made no difference.

[Rod's Trucks]

I cannot help much with the stalling issue; but the oil pressure being 'jumpy' seems very common, as long as it only momentarily twitches a couple widths of the needle. Just watch for a sudden large drop!

The heat issue may be a bad vacuum line and/or a broken heater control valve...both very common problems. On mine, the heater control valve was somehow stuck mostly closed, and then I found out that the heater core was also air bound. The heater core is highest place in the system, so getting the air out of the heater core is more of a process than on most vehicles.
I disconnected the two hoses from the heater core, and back-flushed the heater core with a garden hose. I reinstalled the inlet hose and then put a longer length hose from the outlet to a bucket, got the valve fully open, and ran the engine on a high idle. When I got a good solid flow through the heater core, and re-installed the original outlet hose.
Best of luck to you,
Rod J
Issaquah, WA

[ptysiek]

I think that the catalyst has fallen off and the exhaust is sticking, error p0420