I have a 2001 Volvo C70 2.3 Turbo HP

Warranty ended about a year ago =( Had the turbo, ECU, injectors, Head and more replaced while still under warranty.

Okay so i have an intermittent misfire on cylinder #1, Started a couple months ago. Idle is a little bouncy, nothing dramatic. When you reset the computer and give it gas sometimes it pulls amazing without a problem at all, other times it it will cut out like crazy and CEL flashes and then P0301 shows up.

-I just replaced the plugs, triple checked gap and keep checking for any plug faults.
-I took the fuel rail off and cleaned and swap injectors around.
-I have swap coil packs around and checked for any arcing on the boots
-I have ran completely new wires from the ECU pin to #1 injector and #1 coil pack.
-I have Alldata and have checked and checked for any clues

My next guess would be ECU problem or compression but would that explain how it comes and goes. If i reset the ECU it runs perfect for about 2 minutes sometimes. Switching coil packs and injectors around still left me with the P0301 Cylinder #1 Code.

Any help would be greatly appreciated !!! Thank you guys!!

 

it may be helpful to change all coil packs and spark plugs. another poster had a similar problem and replacing all coils and plugs did the trick

 

All the plugs have been replaced and still brand new. 2 weeks old tops.

And replacing all the coil packs? sounds exspensive =(

 

A vacuum leak can cause a lean condition in that cylinder. A weak cylinder will show as a misfire.

 

Have you done a compression test yet?

 

unless you overheated, have white smoke in the exhaust, or water in the oil don't bother with compression check, its a waste of time.

make sure you got NGK plugs (they are pre-gapped do not adjust them)

75% of the time that is the problem for intermittent misfires. (people with Bosch plugs in there Volvos)

the other 24% is you looked at the coil wrong and you killed it. -- no really, it happens a lot, watching it idle, watching data values, and all of a sudden one dies. Heat eventually kills them.

the 1% is the odd ball stuff you find sometimes like a vac hose, or low battery voltage, and so on.

 

I have seen over 20 cars with burnt valves causing low compression in one cylinder.
That causes a misfire.
It is actually a very common issue down here in FLA.

 

then in that case an intake cleaning would be in order. You can do a compression check, but more than likely there won't be any found issues. Intake cleaning helps a lot of things. BG products BBK while using a air atomizer through the TB will help any car run better,

 

interesting you mention burnt valves here. my experience is that the older model cars and trucks experience that problem, like pre-1995. here in Virginia it is a rarity. Perhaps climate.

 

Perhaps it is.
We started to see the amount if then raise when the gas prices did. Alot of the customers it happened to admitted to going to regular unleaded gas when the prices went up. I also think the ethanol gas has a part in it as well.

 

Thank you everyone for your replies ! I do not believe it is compression because it is a temperamental problem, sometimes it runs perfect but its not that often, and cant find a common "fault" i guess. 70% of the time it misfires

And the plugs are NGK's, I ran them in my old S4 as well.

Update: with this last snow in Colorado of 18"s !!, i was told the car runs worse the colder the weather. And same temperamental number 1 when its warmer. Also was told it cuts out 20-30% throttle and over 60%.

I drive a 2002 Grand Cherokee Limited, my mother drives the C70. So i dont have the car much. Just when she has problems haha. Thank you guys again, ill be playing with it today if anyone has input.

 

I have a very similar problem with a 2003 S60 - runs great ~75% of the time, but intermittently runs awfully missing on at least one cylinder (P0303 and P0203 codes, most recently P0201 and P0301). Then it goes away. Right now, the car drives great, but it's cool and rainy out. On Monday it was 90 F and sunny and it acted up. The problem also goes away sometimes if I drop it in neutral and rev to 4500 rpm or so. But not always. And sometimes it clears up at steady throttle on the highway all by itself.

The intermittent nature and seeming dependence on ambient conditions point to a vacuum issue, but I don't know enough about these cars to say what that might be. Is there something in the fuel system that uses ambient temperature or atmospheric pressure as an input? Maybe something in the emissions controls?

Please update this thread if you have any success!

 

Check the exhaust and see if it is billowing any smoke at the first start up. This could mean a gasket issue. If all is well there, check the mass air flow sensor or o2 sensor.
Mine cleared up after having engine rebuilt and mass air flow sensor changed. I use NGK plugs and K&N filter
02 volvo s60

 

I have similar experience with my S60 T5 MY 2005 - 100,000 miles, intermittent misfire in cylinder #1. Brand new volvo plugs, swap coils are helpless... eventually solved by swaping injectors...

Another problem... could anyone advise how to troubleshoot ALL of my 5 cylinder has fuel lean problem... all 5 spark plugs are white and being justified as lean fuel by quite some volvo members and mechanics... I did change new fuel filter and took 2 bottles of Lucas injector deep clean in 3 weeks... but problem still there...

Hi Tech, could you please advise how to check "vacuum leak", I have VIDA.

Hi Lifesgoodhere, could you please advise how to do the "intake cleaning".

Thank you.

 

This sound like coil packs to me what happen with the Volvo packs is over time the start to fail slowly and this seems to be what you are describing. when the ECU is reset the car sets it self as if the coil are going to fire correctly and like you said after a few minutes they do not and the car adjust to whats happening. Coil packs my suggestion Buy From IPD there HD coil packs are Great and cost a little more but worth it. They have a Great rep and work amazing well on these P2 cars. Coil packs are like MAF don't cheep out because this is a performance based part and effect MPG and just your general driving experience.Stay away from dealer for these part will cost you 2x as much..

$54.95
ipd HD Ignition Coil with 96mm Insulator Boot

$46.95
Volvo Ignition Coil (C30 C70 S40 S60 V50 V70) Bosch 0221604010 | FCP Euro

 

Not sure how its related, but changing my mass air flow sensor resolved my lean air mixture code and the car runs a hell of a lot better