Poor air/fuel mixture?

Hi,

What you described could be anything from an engine vacuum leak, fuel pressure issue, timing, a partially plugged catalytic converter, and so on.

So, we need a starting point. Here is what I need you to do. The truck has an OBD1 system. To retrieve diagnostic trouble codes, you don't need a scan tool. All that is needed is a short jumper wire or even a paper clip.

Follow the directions in this link and let me know what codes are found. They will point us in the right direction.

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Let me know what you find.

Joe

Hi,

If the fuel tank is low enough, parking downhill can prevent the pump from picking up the fuel. As far as the code is concerned, that can be causing a rich or lean fuel mixture.

Since the code is specific to an open circuit, it could be a broken wire, a bad connector, or the sensor itself has failed. There are several other things as well, but this is where I would start testing.

First, make sure there are at least 5 gallons of fuel in the tank. I'm suggesting this because of the hill it is on. Also, just do a quick check of the wiring and connectors to the oxygen sensor. Make sure nothing is damaged, corroded, or disconnected.

Next, follow the diagnostics below. Take a look through them and let me know if you are comfortable performing them and if you have questions.

Let me know what you find. Also, not that the attachments include a description of the code and what causes it to be set.

Take care and let me know.

Joe

See pics below.