Just got some torque master plugs installed in my 98 GS400, now I notice a loud ticking noise when I step on it in a tunnel or underground garage, also a bit at idle, anyone know what could be causing this?

 

how many miles on your ride?

 

sounds like marbles under the car? If so, you may need a coolant flush.
Others please correct me if I'm wrong about this.

 

Engine knock.. It's horrible for the engine. I had the same issue for the past few months, and could not figure out how to resolve it. I ran a half bottle of sea foam (a liquid 'carb' cleaner) through the intake manifold (via the plate on the top of the throttle body with 2 screws attached to it) and it completely cleared it up. Also, have a mechanic check the plug gap. If everything checks out OK, just drop some NGK or Denso stock plugs in; the engine damage (especially if you hear knock at idle - that's pretty bad) is not worth the extra HP. The HP is probably being robbed anyway because the ECU should be retarding the timing to try and stop the knocking. Good luck.

 

Engine damage, you sure? I thought many on CL have these plugs installed...
Car has 105K miles. Also noticed the car takes longer to warm up.

 

Went out and listened to the noise, its coming from under the engine cover on both sides, so spark plug area... maybe they were not installed right?

 

recheck all your gaps and plugs

 

It's unlikely you have "pinging" at idle. I have never seen a car detonate with no load. I DO know that the fuel injectors on some cars (my GS included) can be VERY loud and clickity-clickity sounding...

 

The noise could be heard good from the front passenger wheel well, kinda sounds like its coming from under the car? maybe a hole in the exhaust?

I don't know what to think, but its bothering me.

 

Eliminate the possibilities:

Pull the plugs and check them. Install NGK plugs if you have to and see if the problem goes away. Why haven't you done that already? At least inspect the plugs for signs of detonation. I don't know about the Lexus, but I know that my 300ZX TT is picky about plugs. You have to use the NGK Platinum plugs or else the engine will give you problems.

 

Don't got the tool to take the plugs out, and don't have replacement plugs, its a long weekend here so all the shops are closed.