What octane fuel are you using? I am not certain if the increased resistance causes a lean condition or advances the timing (or both), but higher octane fuel might help. I installed a series resistor on my previous vehicle (Ford ZX2), and it ran OK for a while; it may have made it slightly quicker, but it was back in 99 so I am not sure. It is definately not a substitute for a proper tune. BTW, you may try to connect a potentiometer instead of a fixed value resistor; that way, you can experiment with different resistances to achieve the best performance. This should only be temporary; after about 90,000 miles, my ZX2 would stall at highway speed for no reason at all, and it did some other funky things. I am fairly certain it was due to the resistor mod.