Car is fully warmed up. I was parked at work and noticed it bouncing (happens very rarely). When I rev it up, it goes back to normal...

What could be the problem? The rest of the gauges work fine.

https://www.youtube.com/watch?v=lUSXzpi50iU

 

could be a slight boost leak maybe , mine use to bounce a lil but i have a digital AEM so its extra sensitive

 

Put you a Manual Boost Gauge in lol. Mine did that before, but find out it was the gauge..

 

manual boost gauge? I thought ours is a manual, not a digital...

 

ours is digital. it may look manual but it gets boost readings from the MAP sensors and not actual vacuum.

 

the stock gauges are electronic not digital. They get their signal from the ECM which reads the manifold pressure from the MAP.

Mechanical boost gauge is more accurate

 

Would it be a direct swap, plug-n-play? Sounds like I'd have to run a pressure / vacuum lone or do dome rewiring or soldering...

I'm still under extended warranty from GM with $100 deductible. How much is a manual boost gauge? Just trying to see if it's worth it or just wait until it completely goes and then take it to the dealer.

 

My stock boost gauge went bad, Said i was boostin 30 when I was at 22 so I bought the AEM one and its all good now.

 

Well, considering you'll never see positive pressure while just idling and revving, I'd say the gauge is messed up.
Does it return to zero with the engine off?!

 

Yes. It works completely fine most of the time. When I shut if off and take out the key, it stays at whatever the gauge is at when I shut it down (usually 19-20 inHg).

If I put the key in to the ACC (or whatever is the one before cranking it) it jumps back to 0... It acts totally fine... this only happened twice or so (that I noticed) so I'm not worried about it. at least not yet.

 

Boost gauges run about 150 for a mechanical one. You would have to run a switched power wire to the gauge and a vacuum line to the intake manifold. It's worth it

 

Ok, thanks man. I'll look into that when mine completely fails.