1995 Grand Prix SE Plug Question

I have a 95 Grand Prix with 135,000 that I purchased last year from a guy that really took good care of it and it runs great. My question is I purchased a set of Bosch Platinum 2's and Bosch wire set and installed them 3 days ago. I have since noticed it "bogging" around 3000 once or twice. I have been reading posts about people not liking the Bosch plugs and that AC Delco OEM plugs should be used but which ones should I switch the Bosch out for? The AC Delco Standard plug, the Platinum plug, or the Rapidfire plug? Thanks!

All of the plugs you mentioned will be OK. The rapidfire plugs are a little better for a high mileage vehicle. You may find that the wires are also causing your problem. GM wires appear to work best on these engines as well as OEM coils. It appears that GM did something right for a change when they designed the wires and coils.

Check the thead on spark plugs also listed here. Big-L has some good insite in to the new iridium plugs that AC now has.

I have a 95 Grand Prix with 135,000



Have you ever pulled a plug to see how they are burning??? With that many miles it might not hurt to go one hotter.If your plugs look like the picture in the center you should be fine with stock ones,but if they look a little dark brown to black then it's time to go with one hotter.


http://www.ngksparkplugs.com/images/charttempfiringend.gif

Check your wires really good. I had the same problem few days ago. One of my brand new wires was just bad. It looked good, but when the engine was running on higher rpm u could see the sparks between the wire and engine mounts... looked a little scary, but after i replaced the wire it was all good :)
PS. Autolite wires suck!