[jaypax]

So my 1998 4.3L v6 s10 is running into issues where when I start it when the engine is warm it shakes and has a misfire until I start driving it and it reaches about 2.5 thousand RPMs. There is usually never a code that comes from this but one time i did get a code of a cylinder 1 misfire. I am also running into an issue where the car will randomly quit while I'm driving it with no warning. When it quits the engine rpm drops very quickly and all the lights on the dash turn on then off and no codes come up. This is inconsistent and sometimes i can take long trips where it doesn't stall at all and other times it stalls a couple of times just going on a short errand and the truck usually starts shortly after it dies.
I would love some help trying to diagnose this problem so i can once again drive my truck without worrying about it. Thanks in advance!

Parts I have replaced already in attempt to fix: sparkplugs, crankshaft position sensor, camshaft position sensor.

 

[ShadeTreeMech]

Could be a faulty cylinder 1 coil pack, cracked, going bad, etc?
Could also be in the distributor cap, cracked, corrosion, or even the rotor button?
Could be a clogged, dirty EGR valve too?
g/l

 

[jaypax]

Could be a faulty cylinder 1 coil pack, cracked, going bad, etc? Could also be in the distributor cap, cracked, corrosion, or even the rotor button? Could be a clogged, dirty EGR valve too? g/l

Thanks, also I forgot to mention that all the spark plugs were quite white meaning the engine is running lean. Would that help narrow it down?

 

[ShadeTreeMech]

It can help guide you to a problem but may not be "THE" problem.
And since many people "see" things differently than others, and no picture of your plugs, here's a chart you can look at to "find" your plugs condition and the possible causes.

Reading Spark Plugs Color | Champion Auto Parts

 

[oldeerslayer]

Could be a faulty cylinder 1 coil pack, cracked, going bad, etc?
Could also be in the distributor cap, cracked, corrosion, or even the rotor button?
Could be a clogged, dirty EGR valve too?
g/l

98 has only 1 coil, hence the need for an old fashioned distributor. No coil packs.
I'd try replacing the CMP sensor in the distributor. It's a hall effect sensor and when going bad they can be erratic. Sometimes heat will open a fault inside it. They're easy to change and relatively cheap.
Gotta be a bazillion You tube how to's on it.

 

[jaypax]

It can help guide you to a problem but may not be "THE" problem.
And since many people "see" things differently than others, and no picture of your plugs, here's a chart you can look at to "find" your plugs condition and the possible causes.

Reading Spark Plugs Color | Champion Auto Parts

Yeah very true, i shouldve provided a picture. Here's a pic of one of the plugs, but yeah I believe inside the cylander was a little hot.

 

[jaypax]

Hey so I just noticed when scanning with my scanner and it shows that my ECT temprature is always 390 degrees Fahrenheit. On the gage on the dash is working and shows expected operating temperatures. Does this mean that my ECM is being faulty?

 

[oldeerslayer]

That doesn't make sense. On a 98 there is only one ECT sensor and it is directly connected to the PCM. If it thinks it's 390°F would explain why it runs lean. But if it believes it's 390° why is it sending data to the cluster with the correct temp? I would also think it would try to either shut itself off or at least go into limp mode. Try a new ECT sensor. They're a bunch cheaper than a computer. Look at the connector and wiring real carefully when you're doing the change. Sounds like either the sensor is shorted or the wiring is.

 

[PeteD]

So my 1998 4.3L v6 s10 is running into issues where when I start it when the engine is warm it shakes and has a misfire until I start driving it and it reaches about 2.5 thousand RPMs. There is usually never a code that comes from this but one time i did get a code of a cylinder 1 misfire. I am also running into an issue where the car will randomly quit while I'm driving it with no warning. When it quits the engine rpm drops very quickly and all the lights on the dash turn on then off and no codes come up. This is inconsistent and sometimes i can take long trips where it doesn't stall at all and other times it stalls a couple of times just going on a short errand and the truck usually starts shortly after it dies.
I would love some help trying to diagnose this problem so i can once again drive my truck without worrying about it. Thanks in advance!

Parts I have replaced already in attempt to fix: sparkplugs, crankshaft position sensor, camshaft position sensor.

The Replacement Parts industry thinks you're on the right track.
Don't stop now that you're getting close. Does anyone you know have a quality scanner they're familiar using ? Eliminating the easy unknowns is also a good diagnostic road to travel.