Cat running rough, air in fuel line..

3406 mechanicals dont have return check valves.

 

Very correct. Just a #4 return orifice on the elbow before the return line...

 

No. It doesn't have injectors (per se). It has 7000 series "pop nozzles". If you had bubbles before (or at) the primary, you have an air prob on the suction side before the T-pump. Chances are, it has a factory steel strainer. Check the O-ring in the lid. After that, it's start junkin lines (all #10) or site glass it from the front backwards. Also, and probably foremost, check for algea in your tanks. Seafoam is available about everywhere for that. Good luck!!...

 

Remove the hand primer and check for trash in the ck valves. What year model is it. Earlier b models had problems with the ck valve coming loose in the transfer pump.

 

I believe he said the pump pumps up tight with full filters so the valves are in place and sealed, and the T-pump won't be a factor til it shows no air before the pump inlet

A '92 may well have top mount crossovers, so doin the 5 gallon bucket test should kill the air prob, in which case it wouldn't hurt to drop it all back to the bottom as previous models had (and worked nicely)...

 

Not necessarily on a '92. One that late that has the "steel strainer" (afore-mentioned) is most likely mounted to the frame at the drivers side rear by the rear spring hanger, i.e. it's low enough to maintain more full fuel by being lower than the rest of the system. All can be checked tho.

First, do you have a fuel pressure gauge? I'm guessin not since you said you cracked a "nut" to bleed whatever. The only "nut" on the primary filter head is the STOP fitting (standard thread o-ring port) for your pressure gauge, hence no gauge? Anyway, knowing fuel pressure is a good thing for you now, and in the future. Buying a gauge set would be money well spent.

Regardless, a #10 x 5' with one female #10JIC on one end will tell you that one. Pull the feed off the T-pump and attach the #10 to the pump. Drop it in a clean bucket of fuel and check for proper operation. If still bobbling, re-attach everything and put it in front of the strainer. If still no clean-up, keep moving back til it's fixed, or just junk everything back from there. Drop the feed to the bottom of the tank with the return, add a crossover, and have just one line to the strainer, then to the motor, etc...

A fuel pressure gauge is still the best start for ya tho (and later a timing check to make sure the spool didn't stick in the advance from sitting)

 

I have found debris in the lines at fittings and that stopped up the lines. I'd would try disconnecting the lines and blowing air back though them.. I have even had a fuel cap chain come loose and get stuck in the pick up(Bottom pick-up) for fuel and shut off enough flow to cause the engine to skip.