Possible Transmission / TC problem?
Im trying to trouble shoot my sister-n-law's 2000 ford focus. Car starts great, runs great, sounds great. No error codes at all. However while driving, there is a slight slight slight, ever so slight surging while on the gas. I looked at the rpm's while driving. They were hovering around 1700ish. And while driving down the street, flat road, constant speed and preasure on gas pedal, I noticed the rpms fluctuate around the 1700ish rpms's up and down about maybe 100rpm's or so, mayby plus or minus 150ish.
I would think this would mean the transmission was slipping correct? But it doesnt feel like a slipping transmission, as for example you were low on fluid.
Could it be the TC not locking up properly?
My sister-n-law has said the car at times felt as if it were possesed. Hard jerking and what not, but neither I nor others who have test driven the car have felt these issues. The most I felt was the ever so slight surging while driving. I suppose this slight surging could progress into something more violent after a while of driving but I am unsure.
Can anyone lend some suggestions on what it might be?
There is an occasion when the car is first started where the rpm's jump up and down about 700 rpm, but pressing the gas, or a short drive will smooth that out. And like I said, it only happens rarely.