Good day everyone,
I hope someone can assist here. My 71 1800 has been having a problem. She has the original engine B20E. What is going on is, there is a HARD hesitation while driving at a steady speed/rpm. We have not been able to recreate in the shop. Seems it is only while under load (driving). It feels like a flaper or whatever in the air intake is closing off all airflow for a split second. The hole car then "bucks" hard. Has any one had this condition, and knows what to do? She runs good, and is at 248K miles. P.S. The condition goes away with a slight increase or decrease in rpms. Only happends at steady rpm under load. We have replaced the Throttle Control Switch with a new unit. I have preformed the adjust check. I count 15 clicks than a large gap (around half to 3/4 throttle) then almost full open, I get a few more clicks. This gap makes me think it would be in the area of 50-65 mph on the road, and that's the area where the bucking is hardest. Am I doing doing something wrong in the adjustment of the switch? Could it be ellswhere? This was slightly happening before I added items like the fireball elec ignition, and replaced the injectors. So I don't think that's it, but on these system, I just don't know. I was even thinking timing chain slop?

Help please.