Nissan Repair: 1990 Nissan Pickup Jerking, excessive blowby, oil contamination

Question
Thanks for your input in advanced. My truck jerks with acceleration primarily in the first three gears. It is as if a new driver that doesn't know how to shift is driving. My mechanic has checked the distributer, timing chain, fuel for water, and something else I can't remember. He can't figure it out. Also, don't know if it is related but it is having trouble starting on occasion. It doesn't sound like a bad started to me and my mechanic changed battery and 'tightened a loose starter wire' but that didn't help.

Answer
Scarlett,

It sounds to me like the distributor is contaminated with oil on the optical pickup and shutter wheel.  Have the mechanic disassemble the distributor.  This is pretty easy and it does not even have to come out of the truck.  Remove the cap, rotor, rotor post and cover and under the cover you will find a round disc with slots along with the optical pickup.  There is probably oil contamination and that causes the miss and hard start condition you describe.  So, have it checked out and email me back.  The fix is a rebuilt distributor.  If the engine has excessive blowby as in it uses a little oil that would mean that it is contributing to pushing oil up the distributor shaft and through the oil seal.  A corrective fix here, other than re-ringing the engine, would be to change to Penzoil 5W30 along with a pint of Restore engine additive.  The combination should help compression and reduce blowby to keep the new distributor from getting oil contamination.