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Volvo Wizards, what's wrong with my V-70?!

hi there, I have a hard to diagnose (for me) issue with my '00 non-turbo volvo v-70 (old age notwithstanding - 142K miles). After warming up and running for a bit, especially when say, running errands, etc. the engine will seem to misfire, or hesitate with a jerking sensation, and is accompanied by a small surge in rpm’s. It does it only while in Drive, and Reverse. Neutral will experience a very mild, occasional, “surge”, but not at all like the other gears. It is especially noticeable at a stop, in Drive, with foot on brakes. Upon accelerating, the hesitation/misfire/surge will be prominent in the lower gears/speeds, but for the most part disappear after 50 mph or so. When it first appeared, it almost felt like the brakes were binding, but it was very hard to reproduce. Later it started to feel like a loose spark plug wire, clogged fuel line, vacuum leak, or dirty carburetor.

In response I changed the oil, spark plugs, and fuel filter. The issue went away for a few days but then came back prominently.

Any ideas before I turn it over to the mechanic, and come to find out it’s a faulty Flux Capacitor? Also, I’m having trouble finding a Haynes Manual for the appropriate year. Any ideas on whether another book would suffice?



Correction: the RPMs drop, not surge, and the issue seems to disappear above 2000 - 2500 RPMs, regardless of speed.

  • chris

A compression test would be a good idea at this point.

Check engine light on?

You have fuel injection, not a carburetor.

Check engine light has been on for some time prior to this issue. Even the dealer can’t seem to get rid of it. Gremlins.

pardon my ignorance, but apart from a lack of compression, what malfunction would that reveal specifically? Head gasket? vacuum? something along those lines?

you might have a low rpm lean miss. you mentioned that the check engine was on prior to this problem. is the check engine light on now? if it is you should from there. a low rpm lean miss could be caused by a small vacuum leak, excessive carbon build-up on the egr valve or the pvc valve. it could also be dirty fuel injectors.

Post the codes that the computer is storing back here. You can get them read for free at any auto parts chain store. Use the “P0123” format, not the english translations. Without those codes this is nothing but a guessing game. The car’s computer senses a mechanical problem somewhere.

A compression test would reveal a bad head gasket, bad valve, or worn piston rings. Hopefully your problem is not as dire as that.

My advice was partly based on the faulty assumption that the check engine light was not on.

As mleich has said: find out and post the error codes.

I had a feeling that’s what you were going to say. Let’s hope not indeed!

Will do. I’ll try to stop in tomorrow and see if I can get a read, then post.

Okay, after some trial and error, I received the following codes:
P0304 - Cyl 4 misfire
P0135 - Oxygen Sensor Heater - Bank1 Sensor 1.

Obviously, I’m not the expert, but I would guess the Oxy sensor has something to do with the issue occurring after being warmed up for a while?
Apart from a loose spark plug wire (and a fouled plug) what would cause a cylinder to misfire?

I like the suggestions that Bluboytoy made, my thoughts also. Replacing the faulty O2 sensor may help also.

As reported in the earlier reply, I was able to get codes indicating a faulty O2 sensor, and a cylinder misfire. I took it to the dealership (I know, I know), and they confirmed with the Volvo specific codes. Apparently, I had put in the wrong plugs - 2 prong, instead of 4 prong Bosch. (Really?). So they swapped for the “right” plugs, replaced the O2 sensor, and swapped the ignition coils with a different cylinder. It’s been fine for a week, and then yesterday it started again. Not as bad, but definitely the same issue - after warming up, the jerking, misfiring, upon acceleration, which goes away after getting up 50 MPH/2200 RPM or so.