basically i'm running 87 octane fuel with my sct programmer on the 91 octane setting. i was running 91 octane like a week or so ago but the gas prices shot up into the 3 dollar range so i let my tank run past empty and went to the gas station. i put in the 87 gas, but when i plugged in my programmer into the OBDII port it wouldnt turn on. so basically it's stuck on 91 and i still keep putting 87. is this bad at all for my truck? in 4th and 5th gear my truck sounds underpowered, kinda marble-ish. i think my OBDII might have stopped working because of this one day i tried plugging a blender into my power inverter (which was plugged into the 12v) and it shorted out. then i tried plugging it into the cig lighter and that shorted out too. i have no idea if it had an effect on the OBDII but i hope it's fixable cuz i really wanna get my programmer working again. on an upside, i got 330 miles + on my nearly tank of gas and i think i only put like 16.4 or so gallons. keep in mind i do have 33s

 

Which engine do you have... if its the 4.0 it has a knock sensor
that will retard timing..
if you have the 3.0 you are going to get pinging.

Rand

 

i have a 3.0 so is there anything that can totally screw up my engine or anything else? or will i be okay for now running the 87

 

yes you can damage your spark plugs. there is a fuse for the OBD-II port, check it, and set it to the correct octane

 

ok i'll check it thanks.

 

The fuse for the Data Link Connector (where you plug in the tuner cable) is shared by the cigarette lighter. Check the fuse #17 (20 amp) in the dash fuse panel. Replacing it should get your power back at the DLC for your tuner.

While you're there, you can fix the 12v power point, too - fuse #22, also 20A.

 

oh sweet. so umm.. as far as fuses and such i'm lost.. so how much will it cost to replace?

 

Cheap. Dealer, parts store, WalMart, whatever. Just ask for 20A automotive mini fuses. They should look like the photo (except they will be a different color since they're 20A and the one in the picture is 7.5A). Take the melted one in as a sample.

 

ok whew. cuz i really gotta change back to the 87 setting. so it's fuse # 17? are they labeled or do i have to check the manual?

 

Pull the cover on the left end of your dash and you will see the fuses. The fuse numbers are on the panel, the amp rating of each fuse is right on the fuse itself. There is a small puller tool stored in the corner of the panel to make it easy remove the fuses.

If you need more info, the owner's manual has maps of the fuse locations and charts of the fuse numbers.

 

bob, thanks for the help.

 

worked perfectly man. i finally got to get my programmer working. now, if someone could help me to get my cruise control working again. all the lights on the steering wheel still work but i can't get the cruise to turn on. fuse again? where is this one located? thanks

 

There could be a lot of different reasons why the cruise won't engage. The fuses are a good place to start.

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