2000 V70 AWD misfire cylinder #2 persists

[Rocket99]

2000 V70 AWD 4 speed automatic

I'm 99% Volvo green in the inexperienced sense.

Rough running became evident in an instant, code said CEL and Blue driver code reader said misfire #2 P0302

Drove back home It was a little stinky ie something seemed to have gotten hot. Laser temp reader on the thermostat housing said 211 degress F.

Swapped in a used spare ignition coil and new spark plug Bosch platinum. Still got misfire on #2. verified spark plug gap .027". Several smog alerts activated now, O2 sensor, sensor preheater EVAP, catalyst

with cylinder 2 misfire recurring
-could it be a burnt valve that occured in the blink of an eye? That code clears but it is obviously rough like misfire. #2 misfire reoccurs.

What would be the next steps from you guys who have been around ?
?replace that #2 injector?
- use new ignition coil?

What else to check here aside from compression in #2. Cannot imagine a valve would burn in the blink of an eye.

Are there good quality after market ignition coils, Bosch or others?

Somone said no to Bosch platinum spark plugs.

Thanks in advance
Rocket

[erikv11]

Valves only burn in the blink of an eye. One moment the cylinder holds compression, the next it doesn't.

I think I would check compression first, then check if spark is getting through to the plug while I have it out (wire could be bad). Or you could swap wires if there is enough length, I haven't tried that on a coil-on-plug setup P80 like yours. You can also swap plugs around see if the misfire follows the plug or not.

[Rocket99]

thank buddha compression 120 on #2
And that spark plug is making a spark when the engine is running and that plug is grounded
Even though I have a pea size brain when it comes to Volvos I figure the next step is replace that fuel injector
Letting the engine run for a moment with no spark plug in it I would predict you would smell unburned gas if there was a working injector. Or maybe the injector wire connection is bad
thx Erik

[erikv11]

120 sounds low but not burned valve low. Might want to check a couple more make sure they all read close to 120 on that gauge.

Good idea on the injector. You can swap injectors around and see if the misfire follows the injector, but I would be careful not to tear any of the rubber seals. Some people I have seen test if an injector works at all by pulling the rail set it on cardboard or paper towels, turn the key see if all 5 spray some fuel.

In response to one of your earlier questions, Bosch makes the factory ignition coils they are a the brand to go with for that part.

[Rocket99]

all 5 were 150 and above a few months ago prior to installation of this engine

Its possible it was not snug tightened into the threads

Thx again Erilk

This car scrambles my brain

My all mechanical diesels Dodge and Mercedes are more my style

[Rocket99]

What about this: new ignition coil, new spark plug, new injector and still misfire #2.

will run compression again try to get the gauge tightened though doing so using tortion of a rubber hose aint great. Need a special deep socket

prior compression check was 120 psi, doubt the gauge connector was properly snug

[abscate]

Can you feel the misfire or is it just being reported by P0302?

[erikv11]

Super useful to test all cylinders at the same times, compare the readings.

[Rocket99]

Can you feel the misfire or is it just being reported by P0302?

yes there is a felt roughness , loss of the smooth running prior to this sudden onset code p0302

[Rocket99]

Super useful to test all cylinders at the same times, compare the readings.

yes will do
how to get the compression gauge snug ?