I have an 04 RX-8, 57k miles, no mods, new plugs within the past 10k miles. Recently when I accelerate hard while driving I am getting this popping noise under the hood until the RPMs levle off, and it feels like the acceleration is dragging a bit. Any suggestions on what it might be? It idles fine most of the time, no CEL codes.

 

When you replaced the spark plugs did you also replace the ignition coils?

 

They looked fine, I took them off and cleaned them. It's more of an intermitant problem really, it doesn't do it all the time.

 

There a lot more knowledgeable people on this forum than I...but my first thoughts are:
What type of fuel are you using?.....and a possible detonating issue.

 

Funny you mention that, I alternate 87 and 93 octane on every other fill-up, and when I run 87 I add Lucas Fuel Treatment (have the large bottle for multiple treatements). Normally Exxon, Chevron or Shell. I've noticed minimal idle difference between the 87 and 93, and normally about 20-30 miles-to-tank difference.

 

Keep it at Premium, stop adding so much Lucus. That stuff leans out the gas to clean the injectors.

87 will make your car detonate.

Then clean the MAF and make sure the air tube is on tite.

 

87 will make your car detonate? please tell me that's a joke....and i'll clean the MAF again just to be safe.