Hello, I have a 1998 Volvo V70 wagon (291,300 miles) that had been doing very well until a few days ago when intermittently, at idle (usually at a stop sign but not always) the engine acts like it is going to quit. RPMs drop and hesitates then OK. Acceleration OK.
Just curious what some of the possible issues could be?

Thank you!

 

Could potentially point to an issue with the IAC (idle air control valve). I am not good with the older cars, so I can't help with further diag.

 

Thank you. If it is the IAC, do you know if this one in my 1998 Volvo V70 wagon can be cleaned?

Thank you again!

 

Should be! https://www.matthewsvolvosite.com/fo...ic.php?t=47533

Good walk through for 850, but should closely apply to the 98 V70 as well.

 

which engine? I'd probably suspect an intake air leak is causing a lean idle. Check for vacuum line issues, intake air boots, seals around the injectors etc. It may take a smoke test to find the leaks.

 

2.5-liter 20-valve Volvo B5254S engine

 

Turns out the problem was with the Mass Air Sensor unit. Just had that part replaced and car running fine now. I did learn that if one suspects that the hesitation/stalling is the Mass Air Sensor; just disconnect it and if it is the sensor, the problem will go away. But can't drive the car much with the Mass Air Sensor disconnected otherwise will foul plugs, etc.
That last tip was given to me at an Auto Parts store and it saved the day since it took a while to get into have the part replaced and just the day before, the car would hardly run, but disconnecting the sensor allowed me to make it to the shop!

I do have one other question. My car is a 1998 V70 wagon with 291,300 miles on it. I don't think the Charcoal filter next to the fuel filter has ever been replaced. Should I replace it since it may be as old as the car? Thank you!