Mystery issue from hell
Thread Starter
1st Gear
Joined: Apr 2025
Posts: 1
Likes: 0
Mystery issue from hell
A while back I lost my grandmother and she left me her 01 c5 vette , was running fine with less than 50k on it. One day it started running funny and I went to check everything out while getting gas I figured ig grab some sea foam just as good measure. I noticed some sugar crystals near my tank and my heart sank. I flushed it out and replaced all it could and ran codes. I got the p0300 code but that was it for a while, until I attempted putting it in gear and then it gave me the code for the oil pressure sensor. I replaced that as well as the coils, wires and plugs just for good measure but it’s still misfiring and runs terrible. I ran codes again and nothing this time. I saw ain a separate forum that it may be the maf sensor so I disconnected it and it actually was able to idle for a bit longer before it stalled. I cleaned it and hooked it back up and it began to run as normal but then it quickly degraded and began running rough again.
I’ve been around cars all my life so I’m no stranger lol but I’m at a bit off a loss
I’ve been around cars all my life so I’m no stranger lol but I’m at a bit off a loss
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,500
Likes: 3,999
From: Cape Coral, Florida
If you don’t have a factory level or equivalent aftermarket scan tool and some advanced diagnostic equipment like a labscope so my advice to you is find a diagnostic shop in your area and it doesn’t matter if you have been around cars your whole life…you will just waste time and money…good luck !!
Administrator
Joined: Mar 2001
Posts: 367,976
Likes: 24,705
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
Moved to C5 Tech for additional advice.
Team Owner
Joined: May 2001
Posts: 87,321
Likes: 1,586
From: Western NY
OP, you mentioned "sugar crystals near the tank". Do you actually mean sugar, like you put in your coffee? Was there evidence of someone forcing the gas filler door open, and/or was the gas cap loose? You don't hear of it happening too often, anymore, but if someone disliked you, and wanted to mess with you, they pour sugar into your gas tank, which would mess up your car. It sounds like that may have happened to you. I'd suggest flushing the gas from your car, and start out with fresh gas, and see what happens.
Melting Slicks
Joined: Sep 2021
Posts: 2,555
Likes: 1,213
The 'sugar in gas' is a myth. At worst it would clog your fuel filter/line because sugar does not dissolve in gasoline. I suppose if there were enough it would be a PitA requiring multiple filter changes.
