[SOLVED] New Motor, multiple bank 1 misfires. Stumped!

[cj86012]

Hello all. This is my first post, and looking forward to joining the community. Unfortunately, I'm starting out with problem and any advice is appreciated. I bought a 2017 interceptor that was advertised as with a new 3.5 liter twin turbo motor. Actually, it's 3 years old an 1 month old and just out of warranty. Still, only about 35k on it. I'm assuming timing is OK.

The car idles fine. With light throttle the odo surges. Under load (getting onto freeway onramp) CEL flashes, car loses power and I get several bank 1 misfire codes.

P0300-Random Misfire
P0301-Cylinder 1 Misfire
P0302-Cylinder 2 Misfire
P0303-Cylinder 3 Misfire

No hissing in the engine bay. The MAF is squeeky clean upon inspection.
I plugged in my cheap scan tool and found one peculiar thing.

No live data for
O2 Sensor Bank 1 Sensor 1
O2 Sensor Bank 2 Sensor 1
Further reading has indicated this may be a limitation with my cheap tool failing to read a heated sensor. Screen shot attached.


I'm hoping it's a small thing like a oxygen sensor? High pressure fuel pump? clogged valve or vacuum leak, but with no other codes I'm not sure where to start. The cats are getting hot (1000 degrees) just driving around the block a few times. I got an intermittent P0420 Bank 1 Cat below threshold, but believe this is the result of the misfires and not a blocked cat. Who knows.

Any ideas?

 

[FordFlintrock]

I would first do a compression test on the engine.

 

[peterk9]

Welcome to the Forum.

Peter

 

[cj86012]

Welcome to the Forum.

Peter

Thanks. I wish under better terms. Compression comes back OK. That's a relief. Any ideas on what's next? What about the surging at low speeds? The way the motor cuts out at higher speed feels like a fuel issue, but I'd expect some kind of CEL for such a thing.

 

[cj86012]

Following up. I did a compression test. I tested cylinder 1 and 2 to cylinder 6. All came back 110 PSI COLD. The car runs alright. It just surges at low speeds and cuts out when giving moderate/heavy throttle.

 

[peterk9]

Following up. I did a compression test. I tested cylinder 1 and 2 to cylinder 6. All came back 110 PSI COLD. The car runs alright. It just surges at low speeds and cuts out when giving moderate/heavy throttle.

Have you checked the throttle body?

Peter

 

[cj86012]

Have you checked the throttle body?

Peter

Haven't even considered it until you bring it up. Could it be responsible for misfires in 1, 2, 3?

On that note, it feels like it's cutting out due to lack of fuel, but I have the same question- would this cause misfires only in 1,2,3?

 

[Turdle]

110 psi is quite low imo.

 

[peterk9]

Haven't even considered it until you bring it up. Could it be responsible for misfires in 1, 2, 3?

On that note, it feels like it's cutting out due to lack of fuel, but I have the same question- would this cause misfires only in 1,2,3?

I'm not a mechanic so I looked it up and found this. https://www.carparts.com/blog/bad-t...ng signs of,acceleration and bad fuel economy.

Peter

 

[1sicbronconut]

I'm guessing it's the converter, the P0420 is an efficiency code but a converter that's starting to get plugged up will cause miss fires on the related bank. We see lots of converter issues on police units due to the time they spend idling that tends to kill converters. The only good test it to pull the upstream oxygen sensor or loosen the converter at the turbo, both are kind of a pain and kind of sketchy to drive that way as well

 

[cj86012]

I'm guessing it's the converter, the P0420 is an efficiency code but a converter that's starting to get plugged up will cause miss fires on the related bank. We see lots of converter issues on police units due to the time they spend idling that tends to kill converters. The only good test it to pull the upstream oxygen sensor or loosen the converter at the turbo, both are kind of a pain and kind of sketchy to drive that way as well

UPDATE [SOLVED]

Spark Plugs. Duh. That's all.

It's better to avoid assumptions, especially on these interceptors that are not utilized in the same way as normal passenger vehicles. The faulty assumption that a simultaneous misfire in 1,2,3 pointed to something linking the three and that they would not likely fail at the same time.

In this case, all of the plugs were fouled, the computer threw specific codes for 1,2,3, but all cylinders were randomly misfiring as indicated in P0300.
A P0300 code indicates that a vehicle is experiencing a random or multiple cylinder misfire


There are more issues to tackle, but this one was the one keeping it off the road. See you all soon!

 

[1sicbronconut]

Glad it's fixed! I'd still worry about that P0420 converters don't generally "fix" themselves. I'm spoiled as a Ford Techician having a few more tools to draw from for testing than most folks have.