And, I think we MAY well have reacted wrongly to saserby's question. As I remember (now that I've rebooted my tired old brain), the pre-04 trucks CAN be "chipped" (at the PCM) and I think these things can even be "switch on the fly" jobs. I think ONELOWF has correctly pinpointed what you may have, and if so, it's a "good" thing. (Good on you, ONELOWF!)

I'm in the leave it alone camp now. If it ain't broke, don't fix it.

Do you possibly see a rotary switch somewhere on the dash that has several positions? This would be the "tune changing" control. If not, it doesn't mean anything except that you have a "fixed" tune device.

The thing I suspect you have installed is NOT the I.D.I.O.T. device.

- Jack

 

Thanks for all the suggestions. I think we are on it now. I seem to remember my uncle saying it was a "Superchip" installed in the "computer". I can see the PCM, but cant see the port which seems to be on the top. I don't have any rotary switch, and couldn't find a hidden one. He specifically told me it was to give more horsepower and better mpg. I'll try to pin him down more when I see him next.

 

Hey.

The 'chip' you likely have looks like this:



It's a Single-program canned tune 'chip', that plugs into the J3 diag port on yer EECV PCM, ON THE BOTTOM, (NOT on the top - it's a diag port and needs to be accessible with the PCM in place as-is - having it on the top would be silly) which looks like this ( factory cover removed from port):



Note that this is a Discontinued Superchips product; folks like Troyer Performance no longer sell them - you'll need to contact Superchips direct for any info - and even their website no longer lists legacy products like this one.

IMPORTANT !!! You WILL need to run 91-93 octane fuel to use this device safely if it is the Superchips canned part. In fact most non-custom chips of this ilk have that caveat. If you are running regular 87 octane, either remove it now, or get premium in there asap. Yer truck, yer risk.

In the unlikely even that it is an 4-bank Custom-tune-capable device, like this one (note that it looks the same), you can get it reprogrammed with any tuning you wish by sending it in to a supporting dealer ( like TP, for example):



There may also be a sticker ( or even tape) over the device to keep it from falling out.

It there is nothing there but the black factory port cover ( with a factory seal over it), AND you can't find any evidence of a S.T.U.P.I.D device, the only other option, if yer uncle still insists it's 'chipped', is the PCM was flashed with a tune ( either canned or custom) and then he threw away , sold, or lost the handheld programmer. Those are the sum total of yer options. After that, he's pulling yer leg, and needs some calibration himself, lol.

Finally, tell yer uncle he really needs to keep better records, because this is plain ridiculous

MGD