slight bumping between 45 & 55 mph
 

I've had a problem with my MP5 for some time now. I get a slight bumping between 45 & 55 mph. I guess you can say it's almost a jerk in my car. Anyway, it only seems to happen just after I accelerate the first time after the car has set for a bit (usually on my way to or from work). I dont think it's a clutch problem because it happens after acceleration and when I'm in 5th gear. Is any of this making sense?? Does anyone else have this problem??? Does anyone know what this could be??

if it only happens for the first few minutes after the car has sat for a bit, it's the tires. the stock tires tend to hold a flat spot untill they get warmed up. normal.

Does it feel like the car surges ahead a bit at say, 2500 rpm or so? I wonder if you are just noticing the VTCS butterflies opening....