Transmission, lost second gear

Hi!
My transmission was fine, but yesterday it lost the gear. Looks like it shifts on first, then after it riches high rpm it shifts on the next. So, could be long shift, or missing second gear. Could you please advise me? Thank you.

Check for vacuum leak or blown modulator diaphragm. It could be hanging so long in first it just skips second and goes right to third. The 1-2 upshift is controlled by vacuum to the modulator valve. There is a large metal line (3/8"?) coming off the back (driver's side) of the motor, that runs down to the transmission on the side facing forward (front of car). At the end of it is a round metal unit, that's the modulator. Make sure the line didn't come off, or the rubber ends of it aren't cracked, and pull the line off at the modulator, if fluid drips out, it's shot.

Thank you for answer.
I checked my car with computer, it says P0122 TSP/Pedal Position Sensor A Circuit Low Input. May be Throttle Position Sensor causes this problem? Where is it located? And how to check it?
Thank you.

Yes. The Trottle Psition Sensor was bad, and caused the transmission problem. I changed it, and now transmission shifts good. But I also need to replace crankshaft position sensor. So I bougt 2 sensors, one with wire, another without. But I dont know where they are located. So could you please direct me.
Thank you.

Are you sure the Crankshaft Position is bad?? Usually if they are bad the car will not run- no spark. Its like turning off the key instantly. I've seen them begin to fail, where the car will run for 15-30 minutes then shut off. It can come back on after cooling for awhile (several hours) and run fine 'til hot again. It gets worse as time goes by- til dead. To test this, you can let it fail (get hot), then blow on it with an air hose to rapidly cool it. If it starts right back up- that's it. Keep in mind the Ignition Module (under the Coil Packs) also fails this same way. They work together along with the computer (ECM). Any of these three will usually make the car shut right off or not start, whereas other sensors will just make your car run,... but run crappy.

I believe on your car, the Crank Pos Sens is located low in the side of the block. On the older Luminas, they were on the back side of the block towards the firewall. It is a bit of a pain to get to. It threads into the block. GM used a yellow and purple wire set going to it. I beleive it has a round nipple-plug style connector. Squeeze the sides of the connector in to realease it.The wires from this sensor will go directly over to the Ignition Module pack underneath/behind the spark Coil Packs (probably down low on the front radiator side of the block).

It's also possible it's located positioned up-against or straddling the front Harmonic Balancer/Pully. This is the other common location for them. If so, look down at the pully and you will see the wires going to it. These kind need to have the mounting bracket adjusted for a tight clearance to the Pulley/ Balancer. The sensor is an inductive pick-up and must be close to, but not touching the rotating Pulley. Instructions for clearance should come with the sensor.

Feel free to correct me if anyone has better details on this year car. I assume its a V6 engine involved here. Good Luck!!

That's interesting about the TPS. Didn't think about it causing shifting problems, but makes sense. By chance was it idling high too? Mine went through an "episode" a couple of weeks back with weird shifting, and a very high (1800) idle speed.

Thank you for your help!
After changing Throttle position sensor the transmission became good, but after I cleared codes, computer started showing code P0336 - Crankshaft Position Sensor. So that is why I am going to change also Crankshaft Position Sensor. I have to remove Check engine Light. I need to pass inspection soon.
Thank you again for you help. Just bought Lumina 1998 3.1 recently, and would like to fix it and drive it. I love this car.
Thanks.

P.S. Jeffcoslacker asked: "By chance was it idling high too?". When I bougt this car, that day everithing was fine. But I didn't drive it much that day. Next day I went around city, and found that the engine stopped sometimes when I was taking foot off from the accelerator. Sometimes the idle was to high also. So it didn't work right. Even the engine was too noisy. On the next day I found, that it started shifting wrong. As I told it shifted at the next gear on too high rpm. I connected the computer and it gave me codes P0122 and P0336. I tryed to clear them, but P0122 TPSensor stayed. So I decided to buy TPSensor. I replaced TPS and everithing became fine. But after couple hours Check engine Light came again, so I connected computer again - P0336 - Crankshaft Position Sensor. That is my story. And that is why I think I have to replace Crankshaft Position Sensor. (Besides Airbag Light)

I was just curious. The other day when mine acted up, I noticed first that it was hanging a long time in first, not shifting up until maybe almost 35 mph, then I noticed when I stopped at the next light, it was idling too high. These two things continued happening for about an hour, then went away and the light went out.

I was going to get the code and see what happened. But I have written here before about my intermittant MIL, it comes on every few months with no symptoms and goes out after I get it out and run 85-95 mph on the highway for a few miles.

Last weekend, I went to Springfield to visit family, and was able to keep this pace for almost 200 miles. The car has never run better. Since I don't drive as much during the week as I used to, I think it needs a good hard run sometimes.

One thing off topic I noticed: Last time I made this trip (last spring, about the same time) I still had the factory spark plugs in it at 114,000 miles. I filled the tank when I left, and arrived on fumes. This time, with new plugs, I arrived with about 3/8 tank. Quite a difference! I figured over 220 miles I averaged 24 mpg, over rolling terrain and some minor hills, while never dropping below 75 mph and hitting 100 at least twice for a couple of miles. Not bad for an old car with a lotta miles on her. Good thing I like this car, looks like it's gonna be around for a while.