2016 JKU performance problem

[Fishhead69]

Just purchased my first Jeep, thinking i got screwed!

A week after i got it home it started running rough like a misfire while driving around town, smooths our after a bit on the freeway. No check engine light, threw a scanner at it and the dreaded P0300 code.. no other codes though.. Heard about the technical service bulletin so took it in and the dealer flashed the Computer, ran butter but started throwing the same code and still no check engine light!! Pulled live data, B1 O2 sensors, both of them, intermittently drop to 0 volts, ding heard from the dash, they come back online, ding, they go out ding, on and on. Looked up

Advanced diagnostics data and this is what I see:

Any ideas?? I’m thinking ECM is bad? Or hopefully massive vacuum leak? But why is my check engine light not coming on, even during initial start up.

 

[Fishhead69]

Guess it would help if you knew what my Jeep was,
2016 JK unlimited sport, manual trans, a few suspension upgrades, but nothing under the hood that I can tell.
Thanx in advance for any ideas.

 

[BLACKJKU]

How many miles are on it, could be that it needs a tuneup.

 

[Fishhead69]

50k

 

[Fishhead69]

Well if anyone is interested, i got the Jeep back home, it spent 3 days at my local Jeep dealership just to find out that 1, the factory warranty was void, 2, it had been wrecked 3, cyl 1 and 4 are the random misfire, and 4, they could not find the cause. So it seems that the PCM is bad!! If that doesn’t work then i guess the vehicle is a lemon. Guess i bought a new lawn ornament

 

[Fishhead69]

Replaced the ECM, runs like a dream, for a day!!! Grrr. But good news it it throws real codes now, massive intake leak cyl 1, intake plenum bolts stripped out.
Any ideas on a fix, without replacing the lower manafold, like helicoil, or epoxy in the holes and retap??

 

[Chris]

Wow, what a saga, thanks for all the updates though. The manifold is plastic, so you could indeed do a helicoil. In fact, that is what I would suggest. I had to do that on a spark plug thread on a cylinder head once.

 

[Fishhead69]

Drilled, tapped 1/4 20, used all thread, now upper plenum is studded!!! Pain to remove but it works great!!! No leaks.