1980 911sc sputtering

[ChrisF5]

So I'm driving my 1980 911sc for my typical backroad spirited rip about 45 miles. Car ran great. I decided to fuel up before going home. I had slightly less than 1/4 tank when I filled up at a Shell gas. 93 octane. After fueling up I drove about 5 more miles and was braking at about 20mph and turning when the exhaust started to make a sputtering pff pff sound. After turning and getting back on the accelerator it seem to pull fine when suddenly the oil pressure gauge began to jump up and down. (normal pressure sits at 4) and my oil level gauge suddenly read 1/2 (normal is 1/4 when warm). I immediately pulled over and left car running while I checked the oil stick which read 80 % full.
I decided to drive an additional 1/2 mile to my house at low speed (10mph)and car was slowly bucking in 2nd gear. (As if it was cold)
Any ideas where I should begin trouble shooting?

[EC900]

The easy stuff first; maybe its just a bad tank of gas. It happens. Give the station a call and see if anyone complained about the fuel. I would try getting most of it out if you can.
Check fuel filter, last time it was changed?
Dig deeper: Check the oil for any gas smell and viscosity when cold. Check for engine oil leaks.
Any black exhaust smoke to suggest vac leak? Check on that.
How’s the idle? That oil gauge jumping…was there any engine surging to suggest CIS problems?

[ChrisF5]

Thank-you that's a great place to start. I was hoping to focus easier stuff first.

[mikesarge]

What was your tach doing? Mine acted this way when the voltage regulator went out. It fried my ‘green wire.’ My tach was bouncing around too. Easy enough to check the voltage with it running. If it’s over about 14.5, there’s yer problem.

[kltarga72]

My first thought was you have an electrical problem. You saw two gages act erratically and exhaust sounded differently but you accelerated and engine performed normally. You drove home at 10 MPH in second gear which resulted in the car bucking, my 1980 SC will also buck leaving my neighborhood (small private drive and gravel road) if I don't keep it in first gear.
First check I would make is battery connections, give the engine compartment a good visual check for any loose connections. If all looks good you should look for oil and gas leaks under the car if none I would start the engine and keep checking the oil level as it is warming up. When engine is at operating temperature I would consider driving around your neighborhood and keep an eye on your oil pressure and oil level gage and see if problem reoccurs.
Do not eliminate fuel problems I was just suggesting you need to troubleshoot your problem a little more and see if you can duplicate the issue

[EC900]

Another couple things to check and replace anyway are the old gas cap and oil cap gaskets. On late models a leaky or no gas cap will trigger a bad idle as the air mixture is increased because the EVAP has to be sealed to perform properly. Oh, make sure the gas cap was replaced after that last fill up ! I left two of them at the pump for my Harleys !

[ChrisF5]

Hey, thanks for all the advice. I'm sorry I took so long to post results been busy and just got around to working on my car. I was able to get it fixed turned out it was the fuel filter. I still need to take the new filter out because it was slightly leaking after install. After some searching I realized I need to put fuel safe thread lock on even with the copper washer. Happy to learn with easy fix.

[hootster2310]

Hi, which fuel filter did you end up using?? There seems to be alot of confusion, I am looking to replace my 1980 SC 3.0 fuel filter but not sure which is the right one, did you have to replace fittings to make work?? My original is a Boach 016 but they are NLA.

[ChrisF5]

Part#: 930-110-196-00-M14
Bosh seemed to be perfect fit just had an issue with crush washer first time and had to install second time and they did supply two washers for top and bottom thankfully