Nissan Repair: 1995 Nissan quest transmission, shift gears, nissan quest

Question
About 2 weeks ago I noticed the rpm was staying high for the speed I was driving.  I thought it was a transmission problem.  I took it to my mechanic and he drove it for 2 days and could not get it to act up.  I had him change the fluid and filter since I have never had it done with 277,000 miles on it.  Well it ran fine for the next two weeks when all of a sudden I noticed it happening again but this time I also noticed that when I came to a stop and put it in park or neutral the engine would idle at about 1500 rpm.  Also the check engine light would come on for 1-2 seconds at a time and when it did the van acted like it was out of gas (bogged down) but as soon as the check engine light when off it ran smooth again.  So I had the mechanic check it out and he said the throttle body sensor needed to be replaced which he did.  I went to pick it up and noticed the check engine light would not go out.  I went back inside and they looked at again and said that two of the three wires on the sensor were coming out and they would have to get another sensor and lengthen the wires so they would stay connected.  He said it would be okay to drive it till he got the other sensor in.  On my way home it would not shift right at all now.  It takes about 30-40 mph to shift into second and when it does it jerks really hard then it never gets to 4th gear.  I am taking it back to him to get it fixed but want to know your opinion on this.  Does it sound like a transmission problem or did they just not put the throttle sensor on correctly?
Thanks.

Answer
Hi Peter -

I think the TBS is binding, or, as you suspect, not installed correctly. This device sends signals to the computer on what position the throttle is, subsequently telling to computer to raise the idle, shift gears, etc.

Have your mechanic check it again.

Thanks
aloha
calvin