In cold weather truck sputters a lot and emits a lot of smoke but once it warms up the smoke stops

1989 ALL OTHER MAKES ALL OTHER MODELS
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KEEZYMAN
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I have an 1989 Ford Ranger, 2.3L 5-Speed transmission. Been having a problem with the truck during really cold weather, lately it's been in the 20's. First off it takes a little while to warm up the truck enough to move it, probably 5-10 minutes before i can safely pull out on the road. It's sputters a lot and emits a lot of smoke, and once it warms up the smoke stops. The other problem is when i'm on the highway, i can get the truck up to 75 mph, but that's in fourth gear, with the engine almost screaming at me, but once i put it in fifth gear, i can barely keep the truck maintaining speed, and if i go up a slight incline in the road, i will slow down, with my foot on the floor. I have to shift back to fourth just to keep up with traffic. Strange thing is this, it's now in the upper 40's this week and the truck is running much better, no sputtering and smoking like when it's really cold out, and 5th gear at least maintains speed and even ever so slightly speeds up the truck. Please give me some suggestions for this problem, I've already changed the spark plugs, fuel filter, and fuel pump (old one was shooting fuel through a rotted hole in one of the lines), going to change the wires this weekend, and I have tested the ignition coils with an ohm meter and they test good. Thank you in advance for any help at all.
Feb 21, 2007 at 7:27 PM
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KASEKENNY
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From another prospective, if the air charge temp sensor (IAT) was reading improperly then more then likely you would have some codes and it would run poorly even when it is a little warmer so it is unlikely to be the issue. The ECM on this vehicle will compare the ECT, ACT/IAT, and the ambient temp sensors when the engine is first started as a rationality check.
If they are not within the proper relation to each other, it will set a code against it.

Clearly this could be an issue but it is more likely to be a mechanical issue with the intake valves having too much carbon/oil build up on them or a fuel quality issue. If the fuel tank has moisture in it the fuel will actually freeze or have frozen water droplets in it and they will not ignite and can cause the engine to smoke.

We would need to start with fuel pressure when this issue is happening. Once we know the pressure is correct we can move onto a potential valve issue.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
Mar 25, 2020 at 6:33 PM
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