My 92 Vette is sputtering at the first hit of the throttle but only when you really punch it. If I'm all the way in it, it will sputter maybe twice but climb all the way up through the rpms. Also my coolant gauge just started acting weird. It won't get anywhere near what it should be. It will be about 140 while the oil is 215. I was thinking the coolant could be bad but would that cause the engine to sputter also. Any suggestions would be greatly appreciated.

 

Do both your guages say the same? (analog and digital)

 

While my car is a '90, the readings are always (unless something is wrong) oil runs cooler than coolant. Use the search feature on the forum for your answers, try advanced search works better.

 

Are you getting a 'Service Engine Soon' message on your DIC? Have you pulled the ECM codes to see what errors are possibly being recorded?

 

Do you mean just the analog gauge is acting weird? Did you check the digital?

The analog gauge is not used at all by the computer and has a seperate sensor, so you can pretty much ignore its output except as a backup if you suspect the other sensor is bad. People here often report that their analog gauge is very imprecise, and it typically seems to err on the low side.

If something weird is showing on the digital gauge, however, it is very likely that the computer has no idea what temperature the car is at. Especially if the temp values are jumping around like crazy, the computer will tell the engine to rapidly change how it's running and your car will sputter, or perhaps buck violently or stall if it's real bad.

The plastic connector on the digital readout's coolant temp sensor's pigtail is prone to warping out of contact over time, as an example of what could cause intermittent temp sensing craziness.

 

The analog gauge seems fine but the digital one is the one acting up. How hard is it to change the engine coolant temperature sensor.

 

Fairly easy, it's located on the front of the water pump.

 

I did this a few months ago and it was fairly involved because you have to drain the coolant from the radiator and the engine block. But before you even think about doing this, you must do more diagnosis. In my case I did not do enough diagnosis beforehand and I ended up replacing the ECT sensor when I didn't need to.

You still have not answered if your car is reporting any diagnostic codes or not. If it does, your SES light will illuminate until the code is cleared or the computer loses power. A diagnostic code will instantly eliminate a lot of possibilities of what could need fixing, but you also need to tell us specifically which diagnostic codes are being reported.

Another important question for you is the exact behavior of the digital readout. Does it always give wrong values, or only sometimes? Are the wrong values consistent or random? Or are the values correct most of the time, with only occasional glitchiness? An intermittent would point more towards something electrical, like wiring and connectors, while a consistent problem would tend to point more towards your sensor being bad/miscalibrated, or god forbid, your PCM misbehaving.

After I had replaced my ECT sensor and realized that it didn't do a damn thing and the problem hadn't gone away, here's something that I did to diagnose the ECT circuit: I unbolted and removed my PCM (not hard, one socket can do it), unplugged all the connectors going to it, and used my factory service manual's map of what wire each pin in the connectors went to. If you don't have a factory service manual, buy one, or someone on here may be able to scan the relevant pages for you if you ask.

I applied a regular multimeter to the two pins that correspond to the two ECT wires, and then I wiggled stuff around near the sensor itself and watched the reading. The result was, when the little plastic connector that plugs into the sensor was almost but not quite plugged in, the signal was making its way through the circuit, but when the connector was plugged in all the way, the circuit was broken and the signal didn't make it through, meaning that the connector was so warped and misshapen that it wasn't making contact when it was plugged in. I'm guessing it warped because it's lousy GM plastic being exposed to the constant heat cycling of the water pump.

So anyway, I would not go through all the trouble of draining coolant and buying a new sensor until you've verified that the wiring and other stuff in that circuit is ok.