Hey guys,


84 T/A here, CC Qjet.

I Took my car out on it's first real run this year and ran into a few problems.

About 16 miles out on my 80 mile round-trip, my cruise died, speedo died and the check engine light came on and the car started running rough.

The check engine light goes away when I restart the car but then comes back on later. Still runs rough, stutters under load at lower RPM...

Anyway,

The reason I ask about gas is because I had about half a tank of fuel from last November in the car that i just topped off. If the gas is bad, would it cause the rough idle and check engine light? When I did the paper clip method, it didn't throw any codes other than the standard "12" so it's a "Soft fault", which I think would be related to lean/rich conditions.

Anyway, just looking for some ideas on where to start. Thanks!

 

I've never seen much about it online but on the fuel injection cars ive owned, bad gas can cause it to do just that. Any easy way to test it, is run it empty, and fill her up. If it doesn't go away after halfway through the new tank there may be damage or something else broke. You can probably add a fuel cleaner/octane booster to help. I have done that since gas is pretty expensive, especially with these fuel suckers.

 

Speedo is cable driven. When it goes the ecm no longer receives a speed signal, a code will trip and the cruise (and lock up won't work). Check that.

Shouldn't cause rough running, but fix what you know is broken first.