My '93 940 runs great just about all the time but once in a great while I'll be sitting at a stop sign(in gear) and it will have a quick, momentary stutter or shudder, similar to when the A/C is on and the compressor kicks in. It doesn't do it enough to be a problem but it annoys me and I'm curious what might cause it. Any ideas?

 

My V90 does that occasionally, one little stutter. I assume it's a fuel delivery issue of some sort, I plan to get off my butt and change the fuel filter one of these days and see if that helps. I may be imagining things, but it seems to only do it when I am running lower octane fuel, never with a tank of 93 octane Shell in its belly.

 

Hmmm....that's a thought. Here's another....I do notice when my engine is warm and running in Park, if I step on the brakes, occasionally, the idle dips and fluctuates for just a second. That's a sign that the brake booster hose or check valve may have a leak. Doesn't do it all the time and never when cold when everything is shrunk and tight. Since I get that shudder while stopped, in gear and depressing the brakes, maybe that vacuum leak is causing the shudder?

 

Definitely nothing to do with the fuel filter or octane!
It could be the fuel pump or the electric fan kicking in, or who knows? Slight glitches like that are hard to diagnose.

 

Hey Lev, you're right. I paid close attention to it and it shudders when the fan kicks on. 2 questions: 1-does that mean my alternator's not putting out enough? And 2-aren't the engine controls suppose to compensate? Thanks

 

Well, as in all things, to live happily I try to avoid the pursuit of perfection which usually causes misery. Very applicable to old Volvos with many miles. These cars were designed in the '70's and little glitches like that are a par for the course--we can't explain or diagnose, much less fix, every little lurch, bump, noise, occasional quirk, etc. My cars are pretty spot on and I don't like to cut corners but in the end I don't want to drive myself crazy if they choose to hick up now and then. Enjoy the ride, do less.

 

the fuel pumps run continuously as long as the engine is running, so thats not it.

electric fans, for sure. a/c compressor cycling, definitely.

my 92 740T, which otherwise runs perfectly does that little stutter at idle sometimes. its never stalled, it just stumbles once then recovers and goes back to steady idle. I've hypothesized it could be due to a sticky idle air controller, but its as likely the fan or a/c compressor.

 

The obvious question is "Why didn't it do it when it was new?" Something has to be "not functioning". While searching for info I found quite a few Jeep and Dodge owners who's cars actually die when there's an electrical surge. The popular guess is poor grounding. What do you think?

 

If it bothers you that much throw in a fresh alternator/battery, or trade the car for a Toyota.

 

I like that!

 

What! Sell my Volvo and miss your incredible help? Never!

 

I've had to help Toyota-types too! I just tell them to get a Volvo (to get around oil burning, rust, rattles, and other Toyota issues.)

 

You must be so proud!

 

I am! I think you'd love one though, I never hear about them having electrical "stumbles" or anything annoying.

 

Annoying? Like...oil burning, rust, rattles. Maybe you should start selling them.