Problem with paper feed/sensor

I have an Epson 1400 printer that is great except for one thing: the feed mechanism.

It will often misfeed constantly or erratically. The condition seems to change. I think I have tracked it down to some kind of timing issue related to the sheet sensor. There is a small "L" shaped sensor that comes up to sense whether a sheet has been fed. What I think is happening is that this sensor is coming up slightly early and either missing the sheet or slightly hooking the front edge of the sheet.

With heavy stock the symptom is simply that the sheet feeds through without printing and I have to manually feed another sheet which may print or may, again, simply feed through without printing.

With light stock (and this is what has made me identify the sensor as the issue) I get two kinds of misfeeds:

1. A feed through like with heavy stock.

2. The paper feeds through but comes out bent up slightly in exactly the place where the sensor is located as if something had hooked the leading edge of the sheet in that spot.

This makes me think that the sensor may be coming up early and either missing the sheet entirely or hooking it slightly.

I have a repair manual, but it doesn't identify this issue and the process of timing the feed is so complicated and requires specialized tools (like a microphone setup that allows you to set belt tension by listening to the sound of the belt) that I am hesitant to jump into it blind.

Does anyone have any insights on this issue?

Thanks,

--Kenoli