well I have been using the bosch +4s for a few months now and have a good bit of a miss. I am not sure if it is because the opti is going out or if the plugs are just crap. Thinking about switching to ngks or autolites to rule out the plugs. anyone having problems with the +4s?

 

The previous owner of my car had Bosh +2's and when I changed to the NGK's the car ran much better. Our cars run much better with a single electrode plug and I prefer the platinum delco's, but the NGK's are $4.00 cheaper per plug.

 

I think I will swap to the tr55s. Or should I go tr6?

 

Use the TR55's. The TR6's are mainly if you're using nitous.

 

I have had the +4s in for about 15,000 miles
without any problems. Based on the comments
I have seen, I will likely go to a different plug
when it's time for the cam swap.

I also have the Accel 300+ ignition which may
cover up any deficiency in the plugs. I did go
through a lot of trial and error to eliminate a
lay down around 5,000 rpm after I installed
1.6 rockers. The solution seemed to be a LT4
knock module combined with the 300+ ignition.
I never suspected the plugs but it's possible
they are a contributor.

 

well I figure if the plugs are bad, then it will solve my problem and I will be happy. If the plugs werent the problem, then I will know without a doubt that it is the opti and I will replace it and then car will run good. So either way the car will run right.