bouncing guages
2nd Gear
Joined: Jul 2023
Posts: 2
Likes: 1
Sounds like the oil pressure sender/switch. My '82 was doing the same thing (bounced around up to 80 at idle but normal when driving) and replacing the oil pressure switch fixed the problem. Bought a new one for around ~$50 on Amazon (Standard Motor Products PS-256 Oil Pressure Gauge Switch). On the '82 I found that it was pretty much impossible to get the old one off without a special wrench specified in the factory service manual (Kent-Moore J-28687 Oil Pressure Switch Wrench that I found used on Ebay for ~$10 with shipping).
Race Director
Joined: Nov 2006
Posts: 13,282
Likes: 7,865
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Left hand side of the block, right above the oil filter.
