$2 or $12 sparkplugs?

Any of the Iridium plugs should work well and give you another 80k miles easily. NGK, Denso or AC-Delco. I would pick the lowest cost of those three. I would also stay away from Bosch Platinums as the tiny center electrode is reported to give problems on some applications.

$2 plugs for your car are likely to be conventional and will work fine for a shorter life span, probably in the 15k-30k range. Platinums are the next step up in service life and Iridiums are the longest lasting.

John

Definitely go with ACDelco plugs. I put NGK's in my old Bonnie's 3.8, and it lost gas mileage. When I got my new Bonnie (1996) I used AcDelco and she runs great, and gets around 28MPG on the highway, and that's with the supercharged engine. I went with ACDelco wires as well.

You can't go wrong using what the factory used.

As long as it's running fine, I probably wouldn't mess with it. Plugs and wires will usually give you some indication when they need to be changed.

Dave

The plugs in my car are rated for 100k miles. At 110k, the car was in the shop so I figured I have the plugs changed at the same time. The difference? None. Same easy starting as when it was new, same fuel mileage. As expected, a wire broke while Bob was changing the plugs. He said it is common for the ones on the rear trying to pull them off the old plugs. Worth it? I guess since the car was in the shop it was convenient and now they will last me the life of the car. My 91 Regal is on it second set of plugs at 148k. The first set was changed at 80k.

If the OP does change them, get equal to the OEM and they should last a long time.

Hmmm, the last "AC-Delco" Iridium plugs I purchased were stamped "NGK" on the actual plug. GM has quit making spark plugs itself and outsources production of the stuff that goes in those little blue and white boxes.

John

As far as I know, they are still different plugs.

Jim,

Don't believe everything the service manuals tell you. I have a 2001

3.4 Impala, and my Helms book said the same thing. Ridiculous. You have to be careful, but it's not really a problem - I've pulled and reinstalled my plugs with no hassle.

Most of the work will be done by touch - but they should be reachable. Be sure to use a real spark plug socket (with the rubber piece inside to grip the plug.) And of course, be careful and gentle upon reinstallation to avoid stripping of threads - I always start mine by hand, with just the socket and extension, before attaching the socket wrench.

It's like on my Colorado p/u - to pull the front spark plug, they (the factory manual) say you have to pull a zillion connectors, then totally remove the wiring harness. Uh, no. Not necessary. Or my old BMW, where they said to change a heater core you had to chisel out the steering column mounts. I don't frigging think so (and didn't need to.)

The guys who write these manuals badly need a reality check from their mechanics.

- Larry A.

I changed the plugs on my wife's Impala around 50k, they are cheap enough that replacing them at 50k instead of the recommended 100k isn't that much more $. Stick with the AC Delco stuff. I unbolted the coil pack and moved it out of the way to make it easier to get the rear and didn't have any trouble.

The real differences are located in your wallet. Buying something other than the GM recommended for your car isn't recommended. New plugs will last a hellofa long time nowadays since there is no more lead in gas. Do you see yourself keeping the car past a 'hellofa' long time? As to jacking the engine: I have a FWD Cadillac and I the 'procedure' is to unbolt the rear of the engine and raise it to get to the rear bank of plugs. I was able to get my arm around the engine and with a combination of tools R&R the rear bank plugs. Start any plug by hand only.....crossthreading is a no-no! Dab a bit of dielectric grease on the threads/plug boot and get after it.

Heat breaks down plug wires over time. If those are the originals (80K), I'd change them. Again, use recommended OEM plug wires. Proper maintenance saves money and extends lifespan.....in most everything.....even in people!

Dave S(Texas)

If you've got the original plugs AC Delco plugs in there now, why not get the same type / # that is already in the car.

I went 180,000 miles on the plug wires in my Bonneville before they were changed at around 8 years old. I wanted to change them at 110,000 when it was 5 years old but the Parts Dept at Pontiac said I didn't need them yet.

Good Luck,

harryface

05 Park Avenue 45,044 91 Bonneville 307,187