intermittent stalling problems?

Question

2001 Chevy Astro Van 4.3 liter v6 210000 miles. I have this van with intermittent stalling issues. It will stall without warning in the middle of driving. It will usually stall, and you can pull over to the side of the road and it will then not start again. And instead just turn over for a while. Once you leave it alone for a minute or so it will USUALLY start up. But not always. I ran the codes and it has a multiple misfire code and a MAF sensor code. I replaced the mass air flow sensor and it didn't help. Although, the mass air flow sensor was definitely due to be changed. I was wondering if someone could give me a list of things to test tomorrow when I go to work on it. Or reasons it could be doing this.

Answer 1

Normally on GM when there is a P0300 (Random Misfire) and a MAF code together, this indicates a Restricted (Clogged) Catalytic Converter.



Yes, the Fuel pump is a common failure on this vehicle, but will usually show signs... (Hard Starting) in the morning on a first start of the day!



Fuel pressure on the 4.3L CPI engine is 60-66 PSI (This system must have 60+ PSI or hard starting will be experienced)



The distributor Cap and Rotor are also big problems on this engine!

The distributor is nothing more than a CMP (CaMshaft Position) sensor on this year 4.3L!



Checks:



1. Fuel Pressure, use an accurate fuel pressure test gauge, Spec. is 60-66 PSI and will "Dead Head" at 75+ PSI with the return line briefly pinched off!

Under no circumstances should the fuel pressure drop below 60 PSI at KOEO...(Key On Engine Off)

Or under Acceleration! (58 PSI is not close enough)



2. Distributor Cap and Rotor... Just replace it! if you haven't already!

(Use a good quality replacement or OEM AC Delco cap and rotor)



3. Check the Ignition coil Primary wiring that leads to the coil, (small white wire and a larger pink wire) it is very common to see the white wire break inside of the insulation an couple of inches up from the connector (See if you can duplicate the stall by wiggling these wires while the engine is running.

Answer 2

It's overdue for a fuel pump if it's never been done before. In fact, I'd just put my Nikes on and do it because it can't be trusted anymore but if that doesn't fix it, it needs a distributor assembly.

I mentioned the distributor assembly only because you can buy them complete with the cap, rotor and sensor inside already installed for less money than buying those parts separately.



Mastec has good info about the primary wiring to the coil though, I'd be checking that carefully.

Answer 3

Get the ignition coil and fuel pressure checked, it's typical for a bad coil to cut out when hot, then work again as soon as it cools off.

Answer 4

Hi so what do you expect now the van is 14 years old.it is worn and having covered the sort of mileage it has these faults are common due to age and wear.