gas drinking and code reading

[Techmonster]

Within the past 6 months i have been getting a check engine light that comes on and off after the engine has been warmed up real good and driving well over 60 mph. I have also been getting very poor gas mileage(about 10 in the city and 15 on the highway). My cruise control quite working about three months ago also(not sure if related problem)

I took it to a garage 1000 miles ago and they put a new thermostat new double platinum plugs and new wires. they also said they pulled a code 341 out of the computer "octane adjust service pin open" What in the world does this mean?


Still have been getting bad gas mileage check engine light coming on also same time and crusie don't work. I pulled codes myself last night and also got code 341.

In the past my truck has always gotting about 14 city and 19 highway.

Anyone have any thoughts what this code might lead to? it's the gas mileage thing that i'm most concerened about. Tire air pressure is fine, air filter clean, fuel filter new recently.

94 X 160,000 miles 4x4 4 door Slop-o-matic tranny.

Thanks for any input

 

[Albino 94LTD]

Don't know about that code but you can try;

Disconnect the battery for 10-15 minutes then drive moderately for 30 minutes. That will reset the PCM. I don't remember if it will erase the code or not.

Clean your Mass Air Sensor elements with some residue free electrical parts cleaner while your battery is DX'd. (it's right there and gives you something to do while you wait)

Clean your DPFE, or replace it and the vacume lines connected to it. (relatively cheap item).

Get a bottle of Amsoil P1 intake cleaner, use as directed, maybe even a can of 'Sea Foam' or Amsoil 'Top End Cleaner' to get rid of carbon build up.

If you're not sure how or what these are, do a search for them.

Mine was getting pretty bad mileage (about the same as yours) until 2 weeks ago. I have done all these AND changed oil and tranny fluid to Amsoil synthetics. Now my mileage has popped up about 3mpg in all conditions, I'm a happy camper

 

[MrShorty]

They put a little shorting bar across two PCM terminals and call it the octane adjust shorting bar. I would suggest a wiring diagram to help locate the shorting bar, but, on my '92 anyway, it's located under the hood near where the self-test connector is. Make sure the shorting bar is in place, and the wiring leading from the PCM to the shorting bar is good.

 

[Chew_12]

I know this is a old thread but Im getting this exact same problem with gas milage and all....I do have a Performance chip maybe that has something to do with it? Did you end up fixing the problem>???