Tps still a problem

[bigred4x4]

I had zero problems with the basic autolite plugs in the 6-7 years I ran them before I switched to Bosch,

I did a test drive engine runs a little smoother at idle but still get a small stumble on very light throttle, I'll put the plugs next on my list and go from there.

 

[CDW6212R]

My Mercury has a hard roughness that I've figured is either the cats, or burned valves etc. I had a miss and lean condition off and on for a long while. Now I'm down to doing the cats or the engine. I'm planning to build an exhaust for my 98 Limited, and then use that old cat to swap and test the idea. I'm getting my 99 Limited running again soon, so I can work on the other ones. It can be good to have multiples of the same vehicles, but not always.

 

[bigred4x4]

I'd start with the exhaust I've rebuilt my engine somewhat recently and have done a compression test(passed) and it still does it from time to time as you describe.