My car has 155k miles on it and I've owned it for five years now. Recently, the car has occasionally been hesitating and idling rough, usually within the first few minutes of starting it (hot or cold) but it has been getting worse. When the issue occurs, pressing the accelerator does pretty much nothing as far as making forward progress. Everything else with the car is normal. The spark plugs have been changed recently, but I believe the coil packs, AFM and ETM are original. The forward O2 sensor was replaced about 4 years ago.

There is no check engine light illuminating, but there was code P0134 when I first checked it the other day. I cleared it and when I drove it again today, the same issue occurred, however, this time there were no codes set.

There was a post earlier today from cwbristow about an '02 with a bad ETM with similar sounding symptoms. Could this possibly happen to an '04? Are there additional troubleshooting steps that could be done to determine the root cause?

 

I would say that if you press the gas pedal and nothing happens at all, then it is most likely the throttle not opening. Running irratically could be numerous things...

All you can really do is what I did which is clean the ETM and MAF sensor. If the problem is still there you take it to the dealer. They will be able to plug it in and tell you it's the ETM, or a sensor maybe.

Don't take it to the local mechanic to run diagnostic unless they have they certified Volvo equipment (which is rare), cause you're just wasting money. Volvo will plug it in and tell you what is wrong. If it's something you can fix then you can just pay them for the diagnostics.

 

Thanks for the reply. I'm going to try cleaning the MAF first. I've seen cases more often than not where cleaning the ETM does not resolve the problem and it's kind of a pain in the *** and requires a new gasket as well.

The CEL finally came on tonight. I'll pull the codes tomorrow and find out what it says.