2002 Astro codes p0101 and p0106

[wmako]

I have an 02 Chevy Astro Van with the 4.3L V6. Yesterday it began running terribly, and I barely was able to get it home. It starts ok, and idles ok most of the time, but if you try to give it any gas, it falls on its face, like vapor lock in the old days. My scanner reported codes p0101 and p0106, which I understand to have something to do with the MAF and the MAP sensors. I replaced the MAF sensor, and there was no difference. I replaced the MAP sensor, but this also did not help. The connectors for each sensor had just over 5 volts with the key on, which I understand to be correct. I am not sure what to do next, and don’t want to keep buying parts I don’t need. Any help is greatly appreciated. Thanks.

[old_master]

Have you checked fuel pressure and leakdown? Key on, engine off, fuel pump running, pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the pump shuts off. The engine cover must be removed to check it. There are two steel fuel lines next to the distributor, the service port has a black plastic cap on it.

[wmako]

Originally Posted by old_master

Have you checked fuel pressure and leakdown? Key on, engine off, fuel pump running, pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the pump shuts off. The engine cover must be removed to check it. There are two steel fuel lines next to the distributor, the service port has a black plastic cap on it.

Thanks, old_master. I have not checked the fuel pressure, but will do that tomorrow.

[wmako]

Ok, I checked the fule pressure, and this is what I found.

When I turn on the the ignition, the pressure spiked up to 60psi, and then held at about 53psi.

When I turned off the ignition it held at a little over 50psi. After 3 minutes it was at 50psi. After 5 minutes it was at 48psi.

The truck started right up, and at idle I has 55psi. If I hit the accelerator, it bounced up close to 60psi.

Is that high enough, or below spec? I removed the fule filter yesterday, and was able to blow through it easily, so I don't not believe it is clogged. The fule puimp was replaced about 3 years ago.

[wmako]

So i removed an o2 sensor, and the van ran much better, so it is starting to look like my catalytic convertor is plugged up.

[old_master]

Fuel pressure and leakdown are both borderline. The pump is probably on its way out, but it's not causing the engine to fall on its face. I suspect you're right about the converter clogging up. If it turns out to be a clogged converter, DON'T use a cheapie or you'll have the SES light come on and DTC P0420 will be set. The ECM parameters for the converter are quite narrow. Keep us posted.