Where is the oxygen sensor located on a 88 dodge pickup D150

Anrez, your 1991 Chevy trucks O2 sensor could be located in the Y pipe just ahead of converter or in the front portion of the converter.
Check the attached links,instruction and guides, Good luck
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Under dash, above the brake pedal.

my service manual "Chysler: full size trucks 1967-88,says it's attached to pannel below steering collume

Doesn't sound like the transmission. Your cable is probably stretched out and needs to be replaced. Yes, you can take out the cluster in less than 20 minutes

had same problem a gear was striped out in the gauge set **** speedo fixed it prity cheap an got a 2 year warrenty hope i could help

One of them is located on the driver's side of the motor and connects to the exaust manifold.

here is some info on where to find the o2 sensor and how to replace it
http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?chapterTitle=Electronic+Engine+Controls&partName=Driveability+%26+Emissions+Controls&pageId=0900c15280251917&subChapterTitle=Oxygen++O2++Sensor&partId=0900c15280251810

15 -vehicle speed sensor 52 oxygen sensor- rich mixture.

The only thing that comes out of the exhaust with a wire coming from it, is the oxygen senser. It is right behind the manafold.

There is a temp. sensor on the exhaust manifold that I just switched out on car that done the same thing it would start when cold but once it was hot and you killed the car it would not start back. When this goes bad its throwing the wrong signal to the computer that it is too hot and allowing it not to crank. This sensor was on the left side of the engine if your facing the car from the front. Also It can be tested with a multimeter to see if it is bad.