Car's still not running right


New Member
Jun 9, 2005
Bethel, CT
Hi, I have a 1999 GT with the mongoose Vortech kit. Since then I added just a mph powerpipe and changed my setting on the x-cal from 6% lean a/f (worked best on dyno run) to 2% rich. It was running fine for about 4 months. Then it started to bog down really bad (maybe lug is the word?) not violently though. It happened when i was past about 30% throttle under load, not when I just reved the engine with the clutch in. I changed the spark plugs, the problem was nearly solved. Now it only had power-losing-lugging past about 4.5k in 3'rd and 4th gear, (maybe 2nd too, the wheels spin though so i don't know.) I then changed my x-cal to 6% rich, nothing changed. I changed the fuel filter, nothing changed. I changed my COP boots about 6 months ago, so I don't think they're dead yet.

I've been trying to solve this on my own, but I can't stomach paying someone to work on my car to get this solved. Does anyone have any ideas I could try or anything like that?

Thanks guys
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Check the coils. You get an ohm meter and test them with that. I dont remember what they are supposed to read but if you search it you should be able to find out what the resistance is supposed to be. Also try to make it leaner, you may have too much fuel now that you changed it from 6% lean to 2% rich. I fouled a set of plugs in 2000 miles from having it too rich.