98 Chev 2500 4x4 timing

[mx659]

Recently i bought a 98 chev 2500 4x4 truck from my son in law, i dont know for certain but i am pretty sure its the 350 vortex engine c/w 250,000kms, the day i bought it the lower intake gasket blew dumping coolant everywhere. My son in law claimed his brother was a mech and they would replace the gasket. so they replaced the gasket and all has been good as far as leaking coolant. There are however a few problems that have risen that im not to sure about. I am very mechanical but i have no experience with this engine. 1st problem under a load going up hills it sounds like my lifters are rattling, if i keep my speed up before the climb it doesnt seem that bad. Im thinking maybe the dist was reinstalled incorrectly but what do i know..at an idle the engine runs smooth. 2nd prob at cruising speed (80-90kph) every once in a while the engine seems to miss a beat and then smooth again, could this be a timing issue also? 3rd prob is ever since the lower intake gasket was replaced the oil pressure gauge does not work on the dash and the check gauges light stays on, i checked the sensor and it seems to be plugged in and there is no low oil noise while running. Could this be a faulty sensors or do you think something else got screwed up.

[dougbfresh]

You sure you have a rotating distributor on that engine? I think 98 you dont have an old style distributor. Bet the bearings were comprimised by the coolant-I'd get a mechanical oil pressure guage on it to see if you have very low oil pressure now. Get an OBD scanner on the diagnostic port under the dash to see why the CEL is on. I'm guessing you have a very sick engine inside.

[mx659]

Im going to try a mechanical oil pressure gauge as you suggest to get a true reading on the oil pressure. Im going to try changing the oil to see if that helps. Engine runs smooth other than under a load up a hill, like if your in too high of a gear and lugging the motor even then its really not that bad it just sounds like its getting low on oil. I dont have any scanner tools so off to the shop for that i guess. The light thats on, on the dash isnt the check engine light its the check gauges light as my oil pressure gauge is not working at all ever since the lower intake gasket was changed . On these vortex engines is the dist timing all computer adjusted or could it be installed incorrectly?

[dougbfresh]

Do you actually have a rotating distributor or just a coil pack(s)?

[olddog]

If the oil pressure is good, and the noise you are hearing is pinging, it may be that the knock sensor was damaged or not connected correctly, when the intake was replaced.

[mx659]

so a bit of an update on what i have discovered., I changed the fuel filter and the hick-up at crusing speeds seemed to go away. by accident i realized that every time i filled up at chevron with reg fuel with techron i would have this rattle (sorry it was pinging) when climbing hills. I recently have been filling up with regular fuel at a different service station and the pinging has pretty much disappeared. dont know if chervon is a lower grade of fuel or if it is just the one station. going to try a different chevron station some day to see if it happens again. I always though chevron was one of the better stations to purchase fuel from. Maybe its possible that this motor requires a little higher octane.