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96 s10 PO172 code trouble

1591 Views 4 Replies 3 Participants Last post by  Yardawg
I replaced all 4 fuel injectors about a month ago. Now I get po172 code and my mpg has dropped by about 5-7 mpg. Truck runs great though. I've since replaced EVAP purge solenoid, IAC (failed), plugs and wires, thermostat, and attempted to change ECT sensor yesterday but the new one made the temp gauge peg out hot as soon as I start the truck. So I put back the old one which has always made the temp gauge read kind of low. Any ideas?
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have you tried cleaning or replacing the MAF?
My truck has a MAP and I have indeed check and tested it and it is fine. Have you any ideas as to why the new coolant temperature sensor would make my gauge peg out? My research has kind of led me in that direction but my SCAN tool is reading 190 degrees while running. Maybe it's intermittently failing? No code sets for it though
Could be the wrong Temp unit or defective. Measure the ohms value of the old one cold and new one cold. Then hot in boiling water. See if the same. You could have a bad O2 sensor, a leaking fuel injector, a defective fuel regulator, a vacuum leak, or even a exhaust leak before the O2 sensor(s). All of these can cause the code.
Could be a defective temp sensor I guess. It is a Delphi brand and it is the correct one according to THEIR application chart. It's a 3 wire which is hard to find where I live so had to order one online. The fuel pump and regulator are about a year old. Codes didn't appear until I changed the injectors. Guess I need to tear it down again and see if I can spot if one is leaking. Maybe a bad O ring? Maybe I can see signs on spark plugs to determine which injector? They were put new at the same time. The truck is running great. Just lost 5-7 mpg and that annoying SES light keeps coming on
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