[Jaycee]

2000 S10 with 4.3l and 232,xxx miles. Just did spark plugs, cap/rotor, and plug wires. Runs buttery smooth at idle when it’s cold. Runs rough as soon as it warms up. When we replaced the cap I noticed the dog ears on the distributor were both broken…. But I don’t think that’s the issue because when it’s cold it runs very smooth. When it warms up it runs like it needs new plugs. And now it has a check engine light that it didn’t have before. I can’t take it to autozone and scan it because I have the wheels off to do brake lines. Any ideas or known issues besides the distributor?
Speaking of which…. How do I change the distributor without pulling the engine or the cab? Doesn’t look like there is enough room to get it out.

I also have a coolant leak when the engine is cold but it stops leaking when it warms up… it’s dripping from the fire wall but I can’t find any leaks in that area.

 

[Usagoal]

When we replaced the cap I noticed the dog ears on the distributor were both broken…. But I don’t think that’s the issue because when it’s cold it runs very smooth.

This is something that should be fixed first before moving ahead. It's very likely the check engine light is related to what I assume would be a misfire/multiple misfire. Purchasing an inexpensive code reader probably isn't a bad investment....considering you have other vehicles that can benefit from such a handy device.

There should be enough room to pull the distributor. Just have the cap off when you do it. There is a sticky at the top of the page with instructions to remove and replace the distributor.

I also have a coolant leak when the engine is cold but it stops leaking when it warms up… it’s dripping from the fire wall but I can’t find any leaks in that area.

Is the drip towards driver side or passenger side? It could be a few things including the intake manifold gasket, heater hose, etc. A cooling system pressure tester would be helpful. You could use it to keep constant pressure on the system without running the engine while checking the origin of the leak. A mechanics mirror may also help with those hard to see areas.

 

[oldeerslayer]

If the ears are missing off the distributor what is holding the cap on? Isn't that where the screw holes are?
If it runs great cold and bad when warmed up you might want to check your temp with a scanner, it could be the temp sensor telling the computer that the engine is still cold.
When they go bad they lie. Which would result in too much fuel being injected because the computer still thinks it's -40°C/F
If you go on Amazon you can buy a BAFX bluetooth scanner adapter for your phone for $21.
Then download the Torque app free or better yet get the pro version for a few bucks. Then you won't need to go to Autozone.

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[Jaycee]

The ears aren’t missing, just like the outside edge is broke off leaving 3/4 of a threaded hole so it has a little clamping force on it…. But probably not what it should have to properly hold the cap. I honestly don’t know how it ran long enough to drive it the 100 miles home.

The coolant leak is more on the passenger side. The coolant leak is new since I changed the plugs because I didn’t see any coolant leaks under it in the PO’s driveway or on the street in front of his house…. And I was under it with a high powered flashlight looking at brake lines and fuel lines. First time we started it after tune up is when we saw it leaking. There is nothing coming out of the heater hoses at the firewall. There is evidence of coolant leaking from the weep hole on the water pump, looks like there is a splice on the heater hose that goes into the water pump.

the coolant looks rusty brown but I can’t tell if it’s because the coolant is rusty water or if that’s what dexcool looks like when it needs a change or if somebody mixed dexcool with green….

all the spark plugs looked like it had been running rich but none were fouled or showed evidence of a blown head gasket. No coolant in the oil… I was going to compression test it while I still have the front wheels off

 

[Big Buford]

Sounds like a new distributor is in order....at least a new cap....until then you can hold the existing cap on w/ a zip tie....

 

[aitch]

I'd suggest getting a pressure tester for the coolant system, or have it done. The leak should be pretty easy to pinpoint that way. And if the coolant fluid is rust colored, it's definitely due for a change, and I'd get the system flushed while that was being done. I've used the (premixed) Prestone All Vehicle coolant in my '03 Sonoma with good results, while there are advocates of using only DexCool.

 

[Sandberm]

My intake manifold gasket leaked at the rear passenger corner and ran down the bell housing, I suspect thats whats going on.

Buy a good quality distributer and put that in.

Lots of new electrical stuff is bad right out the box. If the vehicle ran fine before, put the old plug wires back on and see if it runs better.

Why are you doing brake lines? Do you live in the rust belt?

Let us know what you figure out

 

[Jaycee]

It runs better now than it did when I drove it home. I’ll do the distributor…. But I’m going to wait until I do a compression test because this weekend I’m picking up a 70,000 mile engine from a 2003 Blazer because the shop went under and the owner told me I could have any motor I wanted for $200. So I’m grabbing a 5.3l LS, a 5.7l Hemi (future Jeep project) and a 4.3l V6 . So I will have a spare engine incase it’s needed. And if it’s not needed, I will have one for when I do need it.

My Jeep is supposed to use that orange coolant. I bought it new and when I flush it I also use the Prestone all engine and never had an issue…. I was told it would eat away at my timing cover but I’m at 160,000 miles and when this 4.7l dies it’s getting a Hemi.

 

[needawheel]

2wd or 4wd?
232k and being 'new to you': i would expect rotten vacuum hoses in addition to everything mentioned above. i had a vac hose that was pinching itself closed depending on the temperature.
the vac hoses are easily overlooked because they look like window piss hoses

 

[Jaycee]

Why are you doing brake lines? Do you live in the rust belt?

Let us know what you figure out

South west Michiganistan…..

 

[Rhotpursuit]

the vac hoses are easily overlooked because they look like window piss hoses

what does that even mean?

 

[aitch]

what does that even mean?

"piss hoses"

I think the proper term is 'catheter'!

 

[needawheel]

what, window piss?

 

[needawheel]

windshield washer fluid = window piss
i am shocked yall never heard that one...

 

[Rhotpursuit]

windshield washer fluid = window piss
i am shocked yall never heard that one...

Never heard of it before...

 

[ronterry4543]

At that mileage your miss at operating temp may be valve seat recession.

 

[FLORIDA BUTCH]

I had a leak in the bottom of my wiper fluid jug. My mechanic told me my transmission was leaking, and the trans guy told me my engine was leaking. I only found the leak because of the rust trail it left. The wiper jug was new.

 

[Walleye Hunter]

I had to put a distributor into my '02 because of those broken ears. I do not recall any major problems outside of getting things lined back up during installation. You can't get your head up there and I had to use a borescope to see which way that drive was pointing down in there.