ahhh the tilt sensor problem, i dont know why i didn't mention that in my last post, i thought i did but after i went back and looked i just found the issue in the manual and pasted that into my reply.
Good deal, glad you found the issue, those pesky tilt sensors do go bad for some reason and can cause problems like this and sometimes the troubleshooting guide in the manual doesn't necessarily lead you in that direction.

Hello All

Sorry for not posting earlier but I was away on vacation. Problem found...with skyjack not going up all the way.
The problem was with the tilt leveling sensor. Replaced it and now works great again. Thank you everyone for helping.

not sure how old this lift is but based on the newest manual this is the troubleshooting result for 'no lift'
4.2-4 Platform does not Lift
1. Open manual lowering valve V1.
- Close valve. Replace if defective.
2. Hydraulic oil level too low.
- Fully lower the platform. Fill hydraulic tank until fluid is at or slightly above the top mark on the
sight glass.
3. Platform weight excessive.
- Reduce platform load to maximum capacity.
4. Up valve 3H-14 or 3H-14A (Machines with end of stroke limit switch LS3 only) defective or is sticking.
- Check valve. Replace if defective.

knowing the serial number would have a bearing on the troubleshooting of components and selecting the correct service manual.
There are some limit switches on the scissor assembly at the base that could be causing a problem if they are damaged or not adjusted properly or some type of issue with the switch arm/wheels.

Skyjack has their manuals online. Do a search for skyjack manlift and you will find it. You can access service and parts manuals.

Thanks for your reply swoop223

I was looking at that yesterday and noticed another thing. Sometimes
moving the three relays close to the flasher relay...would make the lift go all the way up. I tried moving wires around and nothing. Usually when the skyjack goes up the flasher flashes and it does not. I only see it flash when it's almost down. Not sure if this is related or not. There are three relays attached together by a long screw.
I tried tapping on one of the three relay...the lift would go up once in while. So I had a spare and replaced it thinking this was the issue but not.Same thing happens. Won't go up all the way. Is there a safety switch which prevents it from going up because something is not right?

inspect the control cable running through the scissor assembly
it may have a broken wire in it that is opening up when it gets to a certain point during the lifting.