check engine light on

The truck has 128000 miles on it. I have ben told that there is only one oxygen sensor on this truck.

Iv has new timing an injectors an new head about a year ago.

Get them to scan the data on the short and long term fuel trim-

Verify how many-they should be one before and one after the Cat.

Toy's uses 2 types of 02 sensors-the narrow range and the wide range also called A/F fuel sensor.

Since it runs good some of the time, I feel it is fuel related or one of the catalytic converters is starting to plug. It may be fine sometimes and partially plug others. Of, fuel pressure may be dropping.

There are four wires going from the oxygen sensor to computer. one of them has a braided shield over it,covered with rubber. What is the braided shield for?

YA I'll check that. But it only messes up when the check engine light comes on. No other time.. Seems to be worse after it warms up.

[quote:11b49f1aa4="pelcnlk"]There are four wires going from the oxygen sensor to computer. one of them has a braided shield over it,covered with rubber. What is the braided shield for?[/quote:11b49f1aa4]

The 4 wire one is the heated one- the colors Black/Black and Orange/Brown'/Green and black

The shielded one is probably the heated wire.

Rear Oxygen sensor will be black and brown

If that light is coming on, there should be a code or codes. That concerns me. Do you have access to a real time scanner that can be viewed while the vehicle is driven?

No I don't man. An no it's reading no code.

Something isn't right. I am starting to think there may be a problem with the ECM.

when i shift in to 2nd gear my check engen light comes on & stays on till i turn it off what my be the reason fo this to happen

Hi unludkyduck,

An error has been detected by the engine management system.

Get a scan done at Autozone and get back with the exact Diagnostic Trouble Code for us to proceed further.

I am having the same problem does anyone have an answer to DUSYMAN1986 question or have you fixed yours man. I have a new engine and all in mine and would like to fix mane.

Hey guys,

These trucks have a mechanical MAF that will fail and cause the problem you are describing. Please remove the MAF and check the air door, it should move freely.

Let me know what you find.

Best, Ken