Why does my truck misfire and sputter while cruising?
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A stretched chain will reduce power, but, that's about it. I had almost 180K on my 96 when I replaced the timing set, that made a HUGE difference in how the engine ran. Much smoother, and far more power. Misfiring at steady-state cruise is more likely a mixture issue. Insufficient fueling due to a mis-reporting O2 sensor. Step on the gas, and the PCM goes into power-enrichment mode, and feeds the engine more gas. Step on it hard enough, and it will go into open-loop, and just ignore the O2 sensor completely.
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So I tried driving down the highway with my 02 sensor unplugged and it didn't make any difference, but then I tried again with overdrive off and it was not sputtering or shaking at all. I'm thinking this may have something to do with my overdrive cutting in and out, possibly from a defective sensor or switch or something. Any other possible solutions?
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From: Clayton MI
So I tried driving down the highway with my 02 sensor unplugged and it didn't make any difference, but then I tried again with overdrive off and it was not sputtering or shaking at all. I'm thinking this may have something to do with my overdrive cutting in and out, possibly from a defective sensor or switch or something. Any other possible solutions?
When is the last time the truck had a good tune up? What plugs are currently in it? These engines really don't care much for the rare-earth fellers..... mystery misfires are just one symptom there. Probably wouldn't hurt to test fuel pressure at steady state cruise as well.
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Being in overdrive magnifies any issues your engine is having. It likely is still running rough, you just don't notice it as much when not in o/d.
When is the last time the truck had a good tune up? What plugs are currently in it? These engines really don't care much for the rare-earth fellers..... mystery misfires are just one symptom there. Probably wouldn't hurt to test fuel pressure at steady state cruise as well.
When is the last time the truck had a good tune up? What plugs are currently in it? These engines really don't care much for the rare-earth fellers..... mystery misfires are just one symptom there. Probably wouldn't hurt to test fuel pressure at steady state cruise as well.
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From: Clayton MI
Im not sure about the last time it got a good tune up, i bought it just a few months ago so i havent had it long. I recently put NGK BKR5E spark plugs in it and it seemed to make a very small difference. How could I test the fuel pressure and steady state cruise? (If this is a stupid question I apologize, I'm 16 and just trying to learn)
Plugs *should* be ok. I would have a look at the rest of the ignition parts though, just for giggles.
To test pressure, you need a gauge with a long enough hose that you can read it while driving down the road. NOT inside the cab though please.
Most big name auto parts stores will 'rent' you one, you get your money back when you return it. They are not known for having real long hoses though....
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We all had to start somewhere, so, there is no such thing as a stupid question.
Plugs *should* be ok. I would have a look at the rest of the ignition parts though, just for giggles.
To test pressure, you need a gauge with a long enough hose that you can read it while driving down the road. NOT inside the cab though please. Most big name auto parts stores will 'rent' you one, you get your money back when you return it. They are not known for having real long hoses though....
Plugs *should* be ok. I would have a look at the rest of the ignition parts though, just for giggles.
To test pressure, you need a gauge with a long enough hose that you can read it while driving down the road. NOT inside the cab though please.
Most big name auto parts stores will 'rent' you one, you get your money back when you return it. They are not known for having real long hoses though....
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Unlikely, You can feel when the od engages and it's not fast like an engine miss. Have a look at the cap and rotor, If you replace it ask for a "OEM style" they should give you one with brass inserts not the aluminum ones that corrode and cause problems in a short time. Since you don't know when the wires where replaced get those also. Buy decent quality 8MM ones. And make sure you got them put on the right plug!