1988 Chevrolet Silverado Chevy 1500 5 7 350 Driving Down Highway 70mph

1988 CHEVROLET SILVERADO
195,000 MILES
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JAKEDRAKENBERG
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Have a 1988 chevy 1500 with a 5.7 350 in it. Driving down highway at 70mph. started losing power more and more the farther i went. (This is all in 30 miles) I eventually had it to the floor to keep moving and than smoke started coming out the back end of the truck. Oil pressure dropped extremely and as soon as i pulled up to a stop light it shut down immediately. After 30 minutes. it started right up as long as i kept it above an idle. No knocks or squeals of any kind and had good oil pressure again. Drove it 3 miles and everything happeded again. 30 minutes later i repeated the process and everything happened again. What could that be? anyone??
Dec 3, 2012 at 2:04 PM
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JDL
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How long since a tune-up? Any applicable trouble codes? You should be able to check mil codes, yourself. What color was smoke, if black, check fuel system. It might have been trying to flood?
Sep 8, 2020 at 5:25 AM
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JAKEDRAKENBERG
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I just bought it from a private party a week or so prior. Oil is fresh and is at the right level. The check engine light was randomly coming on while it ran good but that i believe was just the oxygen sensor. The smoke was white or grey i believe. Hard to tell driving down the freeway. What do you mean by trouble codes? How do i check mil codes? Thanks for your help.
Sep 8, 2020 at 5:25 AM
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JDL
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You use a jumper wire between A & B terminals at the datalink connector. Turn key just till dash lites come on, no further. The mil lamp on the dash starts flashing, you count the flashes to get the codes. Your looking for two digit codes.

If smoke was white, maybe coolant getting into the cylinders? Are you losing coolant?
Sep 8, 2020 at 5:25 AM
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JDL
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Here is datalink connector.
Image (Click to enlarge)
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Sep 8, 2020 at 5:25 AM
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JAKEDRAKENBERG
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I did check the coolant and it has went down alot from being full before this happended. If thats the case and i am getting coolant in the cylinders, is it pointless to fix and bring it to the junk yard or what are your thoughts. I have $800 in it and its a very nice truck until this happened. What would you do and what would i be looking at to fix it. Thanks for all your help
Sep 8, 2020 at 5:25 AM
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JDL
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Might be a bad gasket, or the head / block is cracked. Can you do a compression test on the cylinders?
Sep 8, 2020 at 5:25 AM
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