NVUSZ28

iTrader: (5)

Took the SS out for the weekend (I bought it and parked it), and started to do a tune up on the 92xxx stock A4. I pulled the plugs to find them absolutely filthy, and original. So naturally I replace them. Wow what a difference it made. Anyone know how much power you can lose with bad plugs?

RPM WS6

iTrader: (3)

I had a very different experience with this.

I didn't pull the original plugs on my '02 until it had about 103k miles. The plugs looked very good; textbook wear and still looked to have plenty of life left. Afterwards, there was no difference in power at all, and barely any difference in MPG. This car had seen a lot of highway driving though, and regular use of fuel system detergent plus regular MAF cleanings, filter changes, etc.

There is no set amount of power loss with bad/dirty plugs. If the plugs were bad enough that the engine didn't even run, then you obviously would have lost 100% of the engine's potential power. Any other estimate would be pure speculation.

NVUSZ28

iTrader: (5)

Yeah, when I got it, I had to clean the MAF and TB since it was throwing a dirty MAF and TB code. Now it's throwing an AIR code. Brake rotors were warped, and needed new pads. Normal wear and tear. Still need to flush the tranny and the rear dif.

DonP

(years ago) I bought a 1990 GTA with 73K. Changing plugs, wires and rotor made a huge difference.

777

iTrader: (21)

Like RPM said, there's no limit. You could be running on 0-8 cylinders or partially misfiring on any given number of them at a time.

alexnavasws6

Im doing NGK plugs & MSD wires this week. Just trying to find time to do it. I know they are original plugs and wires. 102xxx miles. Hopefully I feel a difference!

Chevyman1968

I'm getting a Lil misfire at low RPMs so I decided to pull done plugs just to look at them. This is what they looked like.