2000 Caravan with Poor Gas Mileage

Autolite Iridium. Seem to be pregapped, but 1/6 was too tight, 1/6 was too open - both by just a little.

Some gas odor – or something that smells like that – from the exhaust is probably not worth worrying about on completely cold starts, as long as it goes away within a few minutes of idling. My truck, my Corolla, and my prior VW RAbbit all did that. If you smell any gasoline odor at all at the exhaust after the engine warms up, that’s a potentially serious problem and need to be addressed. If your vehicle has a distributor, good idea to replace the distributor cap and rotor as part of the job of replacing the wires. The cap and rotor form a bunch of mechanical switches and the contacts wear out as the engine runs. They will stop making good contact at some point, causing weak or no spark in some cylinders. Runinng the engine with overly wide spark plug gaps will eventually damage the coil(s), so if you continue to have ignition system symptoms, consider that as a likely source.

If the engine runs well after updating the ignition system, and there’s no check engine light or diagnostic codes, I’d guess you are ready to ride without further worries.

GeorgeSanJose3d
If your vehicle has a distributor, good idea to replace the distributor cap and rotor as part of the job of replacing the wires.

I thought I mentioned above that I replaced the distributor cap and rotor, but perhaps in a different post. Yes, they were replaced before I started on the plugs. My omission.

I’m seeing considerable wear on the center electrodes of these sparkplugs. I would expect the new plugs to make a big difference. A too-worn plug creates a too-weak spark, and that creates poor combustion and operating problems.

As the energy jumps from the center electrode to the ground electrode (the one connected to the threads), its high heat and high energy evaporates material and carries material from the center electrode to the other. That’s what creates that rounded “nub” on the center electrode.

Other than extreme wear, he plugs look pretty good actually. I don’t see any gas-wet plugs, any oil-wetted plugs, any oil residue buildup, any signs of extreme heat on any of the plugs (like heat-damaged ceramic), or anything other than the wear.

Other than extreme wear, [t]he plugs look pretty good actually.

Agreed.

So here’s the 1st full tankful since replacing the plugs, 19.5 mpg, mixed highway & in town, not much A/C running. Better!!!

Next tank or two should show if this is an anomaly or a reasonable expectation.

That’s about what my 2007 T&C with the 3.3L engine gets in that kind of driving. Up to 22-23 MPG in steady highway sub-70MPH driving.

My 92 Voyager with the 3.0 got about 18 on the road at 75 mph but it had the old 3 speed Torqueflight. My 2002 Town and Country 3.3 got about 23 but it had a 4 speed OD automatic.

Here’s tank no 2 since replacing the plugs & wires, 19.5 mpg (again), mixed highway & in town, not much A/C running.

Since I had a good discount on gas, I topped it up a bit. Curious what the next tank or two calculate in MPG.

Appreciate the comments!