I cannot remember my last tune up. I can safely it’s easily more than 100k ago.
If the engine runs fine is there any reason to do so?
Mark
What does your users manual say? It has mileage/time intervals for various items. If you neglected “tune up”, what else has been neglected?
“tune-up” is usually not listed as such. But there in an interval for spark plug replacement, timing belt replacement, filter changes, etc. All of these are important.
Yes, there are reasons. For example, you may be damaging your cat converter, an expensive repair.
I’ve followed all other maintenance items except for the tune up since mechanics have never mentioned it. The manual says to replace the plugs at 100k and inspect the wires. That I’m fairly certain hasn’t been done. There’s no mention of the timing belt. There is a note next to plugs and wires to see emission control service. I know I’ve never had a specific emission control service. I thought that was only a function of failing the county’s periodic emission test.
I’d change the plugs and wires. Use OEM plugs. Probably distributor cap also.
No timing belt, then you are OK.
Yes there is a reason to do a tune-up, things may seem OK, but you may have lost some spark efficiency that is costing you mileage, performance and making the catalytic convertor work harder.
No timing belt, it is a chain. No distributor cap, it uses individual coils.
Yes, change the plugs. They are probably OK but its time. Replace the wires if they have never been replaced before. They don’t cost much, they are really easy to replace.
If you doing plugs yourself, go in through the wheel-liners. Put the front on jack-stands, take off the wheels, remove the inner fender liners (lots of plastic push-pins and some screws). The plugs will be staring you in the face. Much easier than from above.
Thanks for the good advise as usual. I will arrange to have the plugs/wires replaced.
Mark
I would NOT replace the wires, all to often that is a path from good to bad. I have had the factory wires go well over 200k without a miss.
But the plugs are a different story. They are constantly degrading from the time they are brand new. Its like brake pads, always wearing down and you want to replace them before they go metal to metal. If the plugs reach the point of wear and they start to misfire, they can damage the coil packs. Coils are not the large rugged simple things they once were. Now they are small, complicated (ICs built into them) expensive and somewhat fragile components.
Replace the plugs, but keep the wires. The wires are a crucial part of the system. They have a specific designed resistance to them and that resistance is part of the formula that determines the pulse width, which in turn determines the total energy of the spark. Many after market wires do not have the same resistance. The low resistance wires often advertised are for after market ignition systems like the MDS system. They can and usually do degrade the factory ignition system performance.
If you do replace the wires, use only factory OEM wires from the dealer. As for plugs, use any brand you wish as long as they are double platinum tipped or iridium/platinum tipped. These plugs form their corona at a different voltage than copper or iron plugs and that is important too.
Your plugs need to be replaced…Even Platinum plugs need to be replaced every 100k miles. I’d replace them now.
For plugs stick with AC plugs…they are the OEM plug for GM. You don’t have to buy them from the dealer. If you’re going to replace the plugs…then buy them from a reputable parts store…NOT stores like ADAP. NGK makes real good wires…so does AC Delco.
I strongly disagree with you about not replacing the wires in this particular situation
we have tons of GM trucks of this vintage in our fleet. And it is extremely common to either damage a wire while removing it, no matter how careful you are . . . or you find that it was already damaged before you even started
And no, there are usually no misfire codes before doing the tune-up, because the threshold for setting the code hasn’t been reached
Which certainly doesn’t mean your plugs and wires were okay
And heat shields, which go around the end of the wires, should also be replaced. It is very common to crush a few of them while removing the wires, no matter how careful you are
db4690, that is pretty ironic. I come from the time when you had to replace the resistance type wires just about everytime you changed the plugs, which was about every 12k miles. I usually switched to solid copper or monel core wires. This was on kittering ignition systems, they weren’t sensitive to wire resistance.
I should be the one saying change those wires. But I have always tested the wires and over the last twenty years or so, I haven’t found a bad one.
If the original plugs have been in the engine for 100K and 10 years or more, you may have some difficulty removing them. Before attempting this suggest to apply some thread penetrant to each plug thread, and allow to soak for a few days. Folks here may have some other advice/cautions on removing plugs that have been installed for a lengthy interval. Especially in aluminum heads. The plugs can stick to the head-threads over time and when you remove the plug it can break off or it comes out ok, but it damages the threads in the process. This is more of a problem on Ford trucks as I recall, but something to consider. That’s one reason why many shops advise at least removing then re-installing the plugs on a more frequent basis than the manufacturer’s suggested plug replacement interval.
that is why I said I disagree in this particular situation
IMO, based on my experience at work, GM wires are not particularly high quality
on my various Toyotas, I’ve encountered only a few bad wires
even on my former low quality Mazda Protege, the wires were never a problem