1993 Chevy K2500 still rough hot and dies

I'm still having problems with this truck. It's a 1993 K2500 with the 5.7 motor. It runs OK when it is cold, but is rough and will die when it's hot. It's worse idling in gear than out of gear. It's rough, but
doesn't die when I'm driving at speed, but it'll die shortly after I take my foot off the accelerator. I've replaced the plugs, wires, rotor, distributor cap, and EGR valve. The rotor had some carbon on top. I'm not getting any bad codes at all.
Two things that may or may not be important.
1. When I replaced the rotor, I noticed that the top of the distributor shaft had a thin layer of rust, which I removed. Also, the shaft has about 3 times more play moving foarward and back than side to side.
2. The temperature gage hasn't worked since I got the truck two years ago - it goes up and down when I start the truck, then doesn't move. The sensor sends signals out (long before I had the current problem, the truck ran OK with the sensor connected and ran rough with the sensor disconnected). I get no codes, and the coolant overflow level rises when the engine is hot, so I assume the cooant system is OK.
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I suggest the ETS sensor for computer that monitors engine temp. If bad it can cause cold rich mixture not to lean out when warm and cause engine to run badly.

TheSnoMan.com
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I'm not familiar with the ETS sensor. I goolged "ETS" and got "electronic traction control ". Are you talking about the coolant temperature sensor?
Jim
SnoMan wrote:

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I meant to say ECS (Engine Coolant Sensor) There is two sensors on engine for coolant temp. The one on the head on drivers side is for gage and the one for computer is near thermostat housing. The computer leans mixture out as engine warms up but if sensor is bad it will stay rich and run poorly warm. ----------------- TheSnoMan.com
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I replaced the sensor by the thermostat, but it didn't help. I hope the NAPA guy gave me the right sensor, it looked similar to the one I took out. On their website, the link from the sensor page says "Coolant Temperature sensor", but the title on the detail page is "Ait Charge Temp Sensor" and the picture looks a little different than what I have. It looks like the website is screwy. Does the sensoron the side look different? Is the one one the side only for the gage? I don't want to replace it if it's not likely to be thae problem (I'm getting no codes), but a $15 dollar sensor is a lot cheaper than a trip to the garage. Is that one the "engine temperature sensor"?
Regarding the distributor - I mentioned it because it's more cloppy moving forward and back, but I don't see why it would only be a problem with a hot engine. I've not done much more than simple things like sensors and hoses. Combine that with with temps that have warmed up to 20-below and we're looking at a trip to the shop.
If it's not fixed, I'll be dropping it off at the garage Friday morning.
Jim
SnoMan wrote:

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The one on the engine head is for the gage only. THere should also be a engine air temp sensor as well which could throw things off. It is strange that it is causing you so much grief because the TBI injection is susually pretty darn relaible and easy to fix. I have a 89 4x4 burb that I have had since new and it now has over 180 K miles on it. I hav had very little trouble with it and the only major headache I had with the way it ran was several years ago it would run poorly at time for no reason and no codes. It turned out to be a bad gasket between the throttle body and the intake manifold. I do not think that it applies to your problems but you might check it out. ----------------- TheSnoMan.com
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JimB2 wrote:

    The distributors used in TBI trucks do have problems with shaft free play. As well as magnetic pick up issues. The magnets on the shaft will go bad, as well as the pick up in the housing.
    If you have excessive shaft play, I would replace the distributor with a rebuilt unit. The bushing in the body will need replaced as well as the shaft. These days you can pick up a rebuilt distributor for less then you can buy the parts to repair it for.
Charles
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