[midwestmk2]

Since the car is a factory 5MGE to put in a 7M you will have to swap the entire harness and ECU..If your going to do all that headache just do a 7MGTE instead..Sounds like your alternator has a bad regulator..Go to a salvage yard and get your self a alt and a battery hold down bracket off a N/A MKIII and your charging problems will be gone and your lights will not dimm ever agian,not even at idle at night with the a/c and headlights on..When you battery moves it is grounding out on the radiator(BAD!)..The strap from the MKIII will fix that..Now are you saying that its exhaust gas's or gas fumes??If it exhaust fumes its probably a leak but you would here it..Any exhaust leak on these car and you will know it they tend to be a bit loud..If its a gas fume then you might check your charcoal canister(big black cylinder next to the exhaust manifold)and make sure all of the lines are hooked up..If not or its not there then go and get yourself a venting gas cap and it should solve that..