last weekend i changed the oil line front and back replaced the cpi and did brakes. after i was done and for about a week after that when you would turn the key the motor did a half a crank lock up for bout 2 secs and start right up.it doesnt doi it now tho. today she turned on the truck ans she told me the oil psi was up to 65 70 then went baack to 60 this confuses me it never had that high psi b4. i am in the works of replacing everything. so ifs theres anything i shoul replace let me know..

my 95 with 4.3 vortec does the same thing when i first start it up. Didnt matter if i used synthetic or conventional oil. Just at idle i would sit at 60-65 and would go up to about 75 when the engine reved up when acceleratingand then drop down to about 40 after the engine warmed up. as for the hard start, make sure your battery is in good condition and the all the connections to the battery and starter are clean and tight.

Probably got some junk in the oil and it effected the pressure sensor then blew out and got caught in the filter. As for hard cranking if this is pre-97 then the dist andtiming may need to be set - too advanced causes hard turnover/starts.

bat was replaced last month... it doesnt have a hard start anymore