Problems with my 1997 Buick Riviera

[razer0409]

Just recently got my 97 Riviera with the L67 back on the road she has 107k miles and the previous owner was a WWII vet who babied and garaged her from new. In 2019 on his way home from getting the trans rebuilt he pulled out in traffic and got the front mopped clean off (car had 2 miles more than the shops receipt shows). In 2022 after sitting covered for 2 years I acquired the car and a $500 parts car. About a year of work later she back driving with one issue.

The codes I am getting now are a P0302 (Cylinder 2 Misfire) and a P0341 (Cam Position Sensor). I replaced the Cam Sensor with a new working one and the code will appear sporadically after the repair, so I don’t believe it to be the issue however maybe it’s a clue. I have chased the misfire to the extent of my knowledge bringing me here. I replaced all 6 plugs and put an all-new set of wires on. Swapped the coil packs with known working ones with no luck. Tested the fuel pressure and it all looked good. Swapped the PCM from the parts car and the problem is still there. Also tested for leaks in the cylinder 2 injector but found nothing.

As far as how it feels the problem appears to be sporadic. The main time that I can notice it is when the car is idling. You can see the rpms fluctuate but this is not every time the car is idle, I would say about ¾ of the time it behaves like this. Also, twice I have gotten a blinking check engine light on startup which I found online is cat failure due to a misfire maybe but maybe its another clue who knows.

Any ideas would be greatly appreciated and if anyone wants or needs any more information just let me know.

[Schurkey]

1.  The Riv is not a W-body.

2.  Connect a scan tool, look at the data stream.  Verify EVERY sensor, and computer output--EGR, timing advance, IAC, etc.

3  Blinking MIL means the catalyst is in danger of failure, not that is has failed.

4.  What is the cranking compression pressure of the misfiring cylinder, compared to the rest of 'em?

5.  IF it's not ignition, and IF it's not compression, and IF the fuel pressure is good...that kinda leaves the injector.