This engines been running great and very smooth until recently. In the past Ive had my intake manifold severely crack and inter cooler couplings leaking but neither of those are giving me similar issues to whats happening now. On a cold start the car runs great for about 5-10 minutes then starts to run mildly rough from idle to how ever high i shift under load or no load. Im being robbed of power and caught the temp starting to creep up on one hot day after a very short drive which was odd.
A week prior to this issue my exhaust dump stopped working so i put on the block off plate which could have burned out my magnaflow cat. I almost always ran with my cutout open in the past atleast 90% of the time. I’m going to open the cutout manually tomorrow and clean the O2 sensor then go for a drive in hopes that the cats clogged or tripping the O2 sensor out with my stock restrictive cat back. I just read up a clogged cat has a lot of symptoms related to my issue including the studdering, hotter than normal engine temps and loss of power.
Things ive done
-compression test 147 140 140 145 145 145
-New NGK Iridium BCPR5EIX-11 plugs as well as playing with the gaps going between .8 and 1.1 on both the old unknown plugs and new
-taking apart the coil packs and cleaning/sanding as well as taping them up with electrical tape
-ziptied the coils to the coil bracket to make sure the coils spark goes to the plug and not anywhere else.
-boost leak test came out good.
-PCV valve cleaned and checked out good
-brake booster and one way valve are good
-fuel filter changed, ran the car with injector cleaner aswell
-MAFS cleaned and connections in the MAF re-soldered
-Injectors click fine…my DVOM meter was sketching out so i cant say the OHMs are correct but appear ok
Im almost out of options of what to do, I have a brand new coil pack coming in today to try to find a bad coil. I also have a coolant pressure testing tool coming to better see if the head gaskets going. Im not loosing any coolant or seing any coolant and oil mixing.
Anyone with an RB20 or parts that would be able to lend a hand or allow me to try their ignitor chip etc id gladly repay you in any non sexual way. I’m wouldn’t ask to test your intake manifold or pull off a throttle body etc…just simple stuff. Thanks in advance