Engine Surging
 

I have a 2001 Mustang GT thats stock. When my car is at idle or when I am driving at a constant rpm for awhile....it will surge and drop like 400 rpm or so.....it seems likes its missing or something....it doesnt happen all the time so whenever I ask anyone and it doesnt happen and I seem like a nut....I’ve changed gas stations and and put regular and super in at times...it doesnt seem to affect and it happens when its both hot and cold I only have about 15 k on it and I’ve change the fuel filter and kept up with all the services and stuff......any else have this problem or know what it could be?

sounds like a plug wire loose or some type of computer problem. Especially since you changed the fuel filter. I was having a simular problem but the car would just shut off, sometimes it would buck and the trany go into neutral even while in drive. I battled this for months and finally found a frayed ground wire. Most mechs hate this kind of problem cause it isn't a constant thing. You'll most likely have to eliminate one thing at a time.

Good luck!

Hey Surf,
Where did you wind up finding that freyed ground?

Had a similar problem on the 98 for quite a while until I found the grounding problem. I also went through a new computer too... ugh. Don't you love electronics?