Lets start by laying the basics: FRESH BUILT MOTOR

B18b1 block with CTR pistons
B16 head GSR cams
ITR intake mani 70mm throttle body
Chipped p28 with basemap from reputable Phearable.net
CAR HAS NO CHECK ENGINE LIGHTS
Motor has went through 1k mile break-in
New wires & spark plugs
(distributor looks fairly new/tested volts and all is well)
TPS has been properly calibrated
Timing marks checked as well as Ignition timing set with light.
Injectors tested and are properly working.

After I put the new intake manifold and throttle body on I installed the new basemap chip as well. Drove the car to work and it did great on the way there. On my way home was when I started running into issues. I noticed a slight miss happening so I babied it to the house. Went out the next day and checked over everything to make sure all was well. Drove it again and the same thing, when the car idles it seems to be just fine but if I take it out and romp on it a little you can feel it missing pretty bad.

After this happened I decided to invest in a Compression tester just to see how my compression looked. So the results are as follows
1- 180
2- 180
3- 180
4- 175

I am a little worried as to why the cylinder #4 wont go up to the 180 psi. From what I have read and researched everything should be fine as long as youre within 10+or- psi.

So I guess my question is should I be worried of that 5psi or move the diagnostics onto something else (distributor,firing, etc). Also any other helpful tips will be appreciated I did attempt to do my research also just could not find the right forum for my question.

 

BUMP..