Surging at higher speeds and RPM
 

Ok, this is just recently happening. Driving anywhere from 60-100 mph the car is surging pretty bad. It doesn't matter what gear I'm in, but if it's WOT it will slug real bad. It doesn't seem to happen at all at lower speeds, it still feels real solid. Not sure what the possibilites are, but i have no mods, other then flows, flex fan, and an a/c delete. I am running 89 octane, just replaced the plugs about a month ago, and I gapped them to the factory specs in my shop manual. Plugs are Bosch 2 prong platinum, same ones that were in there before i changed them in which i had no problems what so ever. I'm trying to rule out the idea of bad gas, but other then that what possibilites are there. I was talking to a mechanic at work today, and he said it's possible it could be a plate in the TB ( bad memory so I'm not sure exactly what he said). Thanks

Rosco

Have you replaced the fuel filter lately?

actually, no i haven't. I actually just went through another tank of gas, different station, same 89 octane, and it seems to be a little better with the surging. But the problem is I'm still getting it. I'll have to look into changing my filters. Oh yeah, around what kind of mileage should i be changing my o2 sensors?

O2 I believe to be changed 30-50K. Also I read on some other posts that people were having problems close to what you're having and they too were using Bosch spark plugs and other 'stangers recommended just sticking to plain old Autolite copper plugs (But I guess if you were using them before that wouldn't apply). Could there be a bad plug(s)? I heard of some coming from the factory like that, broken center electrode inside the ceramic.

Yeah, its always a possibility. Well, I'll just stick with all the stuff until winter comes. Going off the road soon for winter, and a paxton.

why r u running 89 octane?