new hg and head now have some misfiring

[1TUFFDSM]

i recently installed a new mitsu 4 layer, arps and got the head machined, got it all together and started right up, timed it and drove good untill i threw some boost at it,(5-10 psi) and i took it well, then come to slow down and stop, the car starts to missfire and sound like an " wrx". then it will eventually it will clear up and drive normal again untill i boost again and the problem repeats it self. then if the car dies it will be hard to start back up, you whould have to hold the gas down to start it and when it starts it be missfiring, also i notice when this happens i hear like a static type nosie coming from the motor, and the wideband is everywhere. im stumped on the problem. the car ran great prior to the tear down.

things ive done so far are:
1.boost leak test up to 30psi : found some small leaks at couplers fixed
2.checked timing at the crank, and made sure all the marks lined up.and ignition timing 4123
3. new ngk plugs and ngk wires
4.checked dsm link for any codes
5.swapped out the 2g mas for another one no diff

car:91 tsi awd 2.0 stock bottom end 150k
mods.

DSM link,external wg MHI e316g,evo gt mani,evo3 o2,BC 272s,mitsu 4 layer,arp studs ,wb190,FIC 650inj,2gmas,AEM wideband o2,ACT 2600 fidanza flywheel. in the box waiting for this problem to be fixed is JMF "RACE" SMIM

any ideas on my situation thanks

 

[matt98eclipse]

Do a compression test and post up results.

 

[1TUFFDSM]

when i was going to do the comression test i found out some terrible news,#2 piston has touched the plug and shut the gap!!! i did the compression test 4321 148 148 125 148, the 125 is the one the has the lowest compression what will casue this , this wasnt like this a week ago now all of a sudden this, wtf

 

[kahl23]

Put some oil in the cylinder, if compression rises it's probably rings, if it doesn't then it could be something in the valve train like a bent valve or a valve seat that wasn't machined right etc.

 

[1992awdlaser]

Put some oil in the cylinder, if compression rises it's probably rings, if it doesn't then it could be something in the valve train like a bent valve or a valve seat that wasn't machined right etc.

Compression is going to rise unless there is a hole in the piston if you put oil in the cylinder. The oil will sit in the dish of the piston. This will make less space for the air to occupy which will raise the compression numbers.