Uneven cycling in drive with brake depressed

[TJWookiee]

I was coming here to ask opinions on what might be happening with my 2006 xc70, and I think I stumbled on the answer, but I'll ask anyhow.

I've recently had a cracked radiator replaced, and also had the timing belt replaced a few months back. Since the timing belt was replaced, I've felt a sort of rumble or vibration while in gear with the brake depressed, like at a red light. It kind of sounds like a washer if the load is unbalanced. Any suggestions on what to look for to determine the issue?

[Vova585]

Sorry, but there can be many explanation for your symptoms. You are basically putting the engine under small load with putting it in gear. In order to tell anything next, one need to have access to the good scanner tool. I would look if you have any pending or active codes(you would probably report check engine here). If no codes, then you have to look at long and short term fuel trims to get an idea is it due to lean or rich condition(most likely lean) and then work from there. Dont throw parts at it and better diagnose exactly what is wrong since you can put plenty of parts and get nowhere.

[jonesg]

put it in gear , foot on the brake and blip the throttle, watch engine mounts for excess movement.

[TJWookiee]

Appreciate the responses, thank you. I don't think my mechanic knows to reset the fuel trim so I'm going to start there and see what happens.

[chrism]

What if you use the parking brake to keep the car from rolling? I’m thinking that if it’s only when you are holding the brake pedal down then maybe you have a leaking brake booster or the associated vacuum hose.
Do you get the same feeling roughness when in reverse and holding the brake?

[TJWookiee]

Yes, same rumble when I brake and put in reverse I've noticed in past. I'll try with the parking brake to confirm.

[br0dy519]

Definitely engine mount, or a coil starting to go bad and small misfire.