[RyanAK]

UPDATE: I thought I had this solved, but it’s back and I’m in the middle of a 1,200 mile trip. The saga continues with post #35. HELP!!

Hey, gang. My daily driver let me down a few weeks ago and put me dead on the side of the interstate 100 miles from home. I’ve methodically gone through diagnosis, fixing or replacing things and THINK I have it solved. I had been able to duplicate the fail a time or two close to home as I worked through my list, but as I completed the last few items I haven’t been able to repeat the condition that left me stranded. BUT... lack of evidence doesn’t mean I have it solved and frankly I’m a little nervous about my next 280 mile commute.

So... the truck: 1978 K10 Suburban pretty bone stock with a GM crate installed by the previous owner. About 18,000 miles on that motor now. Carter Quadrajet, TH350, NP203 (stock), 3.73 gears. The only ‘upgrade’ to the drivetrain would be 16” wagon wheels and 275/75R16 tires.

What happened? Well... Cruising home on I-80 from work near the Delaware Water Gap I hit the LONG grade up into the Poconos at Tannersville. This grade is a grind. Something like 8 miles of 4%. I’m doing 70, keeping up with traffic. Truck is working, but not struggling. Normal. Have done this drive several dozen times. This time however, I get a sudden series of surges and deaths. Sorts like running out of gas. Something like...

La la la going 70 up hill, all is right with the world, la la la.... booooog GO!!! boooooooog GO!! booooooooooog GO! boooooooooog Go. booooooog Go? boooooog go? no? dead. On the berm of 4 lanes at rush hour where two interstates diverge. I have tools and some ability, but I also have two young kids and a wife that like me pretty good. Tow truck.

Get towed to the next exit, Dad drives down to meet me. Fiddle around, get it started. Go for a slice of pizza with Dad. Talk about what we should do. Screw it, let’s try.

Dad chased me home. All good except for one long grade again where it started to do the same booooooog GO!, but not as sever this time. Got it home. Started in on it the next morning.

So... before I go into the long list of relatively small things I did to the truck, I’d love to hear any suggestions for what the cause might be. There are only two things left on my list to try, but as I said, I haven’t been able to replicate the symptoms again.

Thanks in advance. Hopefully I have this licked, but if not, I’m sure someone will suggest the best next move.

Ryan