Go to E-bay, and type in "PT Cruiser performance chip". You should see a few pop up. I am using one right now, it only cost $0.99, and it's working with no problems. It's just a resistor that tells the computer the air coming into the engine is cooler than it really is, so the engine in turn is fed more fuel and the timing is advanced slightly. I noticed a bit of a difference, it works quite well with an aftermarket intake. I would say to invest the .99, and if you don't like it, just throw it away, but you should notice something... as much or equal to JET or Belle chips.
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