fattypros

ok, im about to throw in the towel on this....please provide some guidance.

about a month ago, i was driving the car off and on, sticking to my truck for regular travel, well one sunday, i drive about 5 miles to the store, a beautiful day for a drive, everything was good except for the low oil pressure, a problem i have been putting off becuase i was getting together money to do my mods that i have had in planning for a year. well heading back from the store, the car started jerking, at any throttle rate, just not a smooth acceleration. i have had misfires in the past, cuased by my messed up opti, switched it with a dynaspark, and new plugs and wires, and everything worked great.

but back then, it sounded off, with more backfiring and the SES light would be on, and sometimes flash. now i have no SES light, and it doesnt seem to do it when the car is cold, and oil pressure is around 40 as opposed to 20, when the car heats up and my oil pressure goes down....is when it happens?

i have a new oil pump standing by, and the car is ready to be put in layup, im hoping that the pressure issue will be fixed by the new pump, but do you think this wierd misfire is caused by the low pressure?

sorry i cant associate it with anything else besides that, i've be reluctant to drive it. i drive it maybe once a week, for about 10 minutes, just around the block to see if there are any changes, but nothing.

help!

also, im getting ready to do my mods, is there anywhere online (besides the numerous people on these boards, thanks for your help in past issues) i can find as a good guide for my head and cam swap, header install, hardtop to ttop swap? as i always say, any help appreciated.
thanks, nick

transAMdriv3r

im not sure if the oil pressure would have anything to do about the jerking, but in a work truck i used to have one of the fuel injectors were bad and it would not go over 40 mph without it jerking. thats my .02 cents i would get more feedback before you tear it apart though, could be something else.

Injuneer

Probably wouldn't hurt to include info like the year of the car and any major mods. Not all years of the LT1 are the same. The fact that the SES light would flash would seem to indicate its a 96 or 97 OBD-II????

Also more details, like at what RPM is the oil pressure only 20psi? It would be fine for idle, not so good at 5,000rpm. How long after a cold start does it run fine? Does it start to run rougher after about 3 minutes when the PCM goes into closed loop? No SES light, but have you had the PCM scanned for codes, since not all codes turn on the SES light?

fattypros

sorry, forgot about my sig, it is 20 at idle, goes up to about 40 when you throttle it, the care starts to screw up after it warms up, not just 3 minutes. I have yet to scan for codes

Injuneer

20psi at idle is maybe a shade low, but not unusual for an engine with some miles on it. GM specs require only 6psi at idle. 40psi at 2,000rpm is normal and fine. You need roughly 10psi per 1,000rpm.

If it falls on its face when it transfers from open loop (cold start) to closed loop, its often related to the O2 sensors or air/fuel problems. If it only acts up when the engine really gets warm, it can be something sensitive to heat, like the IC Module or the optical sensor in the Opti.