Hello everyone, here is my Idle RPM reading and MAF reading. Freshly rebuild engine with 2k miles on it. Is this normal?

 

You have a small vacuum leak, at 800-850 rpm idle, the MAF should read 5.5-5.7 g/sec. Is the A/C on in this run? The compressor turning on and off can cause little drops like that, but yours are not regular so probably not what we're seeing here.

 

Thanks for the reply. The AC is off. I don't see any obvious vacuum leaks, all the manifolds are in decent contrition. Is there any else possible reason?. Also does any one knows what this values mean in service manual.

 

What engine and year is this? That 3.8-4.7 g/sec at idle doesn't sound right for a renesis at all.
What is your long-term fuel trim at idle? I'm expecting around +12-15. That would confirm a vacuum leak.
One commom vacuum leak that's missed is the VFAD nipple under the throttle body out of sight.

 

Had a similiar issue when 2 of my vaccum lines decided to go kaput.
Fixed them n this issue was solved.
Check for a vaccum leak as loki suggested..

 

This is from https://www.rotaryheads.com/PDF/RX8/3EngineDetails.pdf page 301. I am not sure if it is correct spec. You are right, long term fuel trim is about 14%. VFAD nipple is closed. For how big of a leak Am I searching for? I don't see any broken vacuum connection. Thanks!

 

I still cant find any broken lines. But as it looks there is definitely a leak. Thanks!