ok just installed a set of E3 spark plugs, runs fine till you hit 3700rpm whats up. no other mods made just heard thay were good for fuel milage. it gose into limp mode. rpms seems to come up quicker now, but the revlimiter should be higher than around 3700rpm right?
Not sure on the E3 plugs. Never used them. I have read some posts on here that the Hemi is pretty picky on what plugs run fine in these motors. Alot of guys run the same copper plugs that the factory ships. For my car, when I changed the plugs out I installed autolite platinum plugs and my car runs fine with them.
My guess here is that the plugs are failing at the RPM you posted above and Misfire is the most likely cause here. Are you getting any codes popping up from your engine? My suggestion would be to get a different set of plugs in there before something bad happens to your engine and see if you can return those plugs. Any of the posts I found either here or on several other forums people have had problems with these plugs and most people said that their car would misfire like crazy.
Last edited by Mindslayer; 04-27-2012 at 12:30 AM.