Get the TR-55's in tommorrow... after reading all the post about the TR-55's I think there should be a big difference seen... When I pulled my +4's out after 35K miles they look pretty bad... like Toasted. I think they might be causing some of the stumbling I feel in the engine. Anyone using hte Bosch Platinum 4's have that issue??? They stopped making hte Plat 4's .... I guess there was a reason for that...

 

I tried Bosch +4s' and didnt notice a difference.... After pulling the plugs out at 10,000 miles, I found that the spark was only jumping to two of the four electrodes on five of the eight plugs....

Waste of money IMO....

 

TR55 is a good choice for a replacement plug. Some people gap them at .040 instead of the .050.

 

Here is what the worst +4 looked like when I took them out after 14,000.

Fugly Plug

I can't say they were hurting me, but there is not much positive feedback on
this board regarding Bosch plugs. I went with the Delco Rapidfire #14s. The
plug was from #8 and the exhaust valve stem seal was pretty toasted.

 

had the bosch P4's and changed to the TR55 - big difference- the bosch didnt seem to work to well