Q: van stalls at about45mph and hesitates on 2000 Nissan Quest

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
mechanic says its many things plugs/allwires tune up trottle cleaning,no check engine light? all motor mounts bad mehanic thinks is all related.
(2) Answers
Poor maint? Put factory parts on including plugs and wires. Fix safety items first...Is it actually stalling(shutting off) at 45MPH or is it just a horrible hesitation? As you can tell no check engine light does not mean no problem. Scan with scanner able to read live data might give better idea of what's happening at 45. could be totally unrelated to tune-up or motor mounts although both might be quite necessary.
I just had this same issue with a 2000 Nissan Quest and a very similar symptom 15 years ago on a 92' HardBody 4x4. No check engine light with a P0325 Knock Sensor Code. I had changed the plugs, wires, rotor, and cap not too long ago so I just double checked everything. I removed the Distributor Cap, then the Dust Cover and thoroughly blew-out the inside of the distributor with an air nozzle (not too much pressure). Problem solved-It seems that there's dust/metal flakes from within blocking the hall effect switch that makes it fire. I was having a real nasty hesitation and back fire from this.