Car idling rougher after dealer visit

Joined
Mar 15, 2019
Messages
49
Location
USA
Hope you fine gentlemen can offer some input about the issue.

I very recently took the car in to the dealership for some service. I had the transmission mount replaced, valve cover gasket replaced and did general maintenance such as tire rotation. I knew the mounts, whether the engine or the transmission, needed some attention since this car seems to always have this issue. I've replaced the mounts on this car several times already.

After driving away, the car idled very rough when I stopped at the stoplight; like it wanted to cut off and it was even shaking mildly. I called the dealer and the main service advisor suggested that I drive the car very hard to "clean it out" because the technician forgot to do it. I didn't inquire further and did as I was told. I drove it *hard and fast* for several miles. This seemed to have smoothed the idle a little bit but it still idles rougher than before. When in drive, it idles rougher than when in park but its generally louder and has more vibrations than before. I mean even with the broken transmission mount the car was way smoother than now. I'm going to go back eventually to have this looked at but just wondering what could this be?

The car has a bit of mileage but is doing well mechanically: Mazda 3 with almost 284,000 miles. The spark plugs and air filter have been changed recently.

I'd appreciate your help.
 
Hope you fine gentlemen can offer some input about the issue.

I very recently took the car in to the dealership for some service. I had the transmission mount replaced, valve cover gasket replaced and did general maintenance such as tire rotation. I knew the mounts, whether the engine or the transmission, needed some attention since this car seems to always have this issue. I've replaced the mounts on this car several times already.

After driving away, the car idled very rough when I stopped at the stoplight; like it wanted to cut off and it was even shaking mildly. I called the dealer and the main service advisor suggested that I drive the car very hard to "clean it out" because the technician forgot to do it. I didn't inquire further and did as I was told. I drove it *hard and fast* for several miles. This seemed to have smoothed the idle a little bit but it still idles rougher than before. When in drive, it idles rougher than when in park but its generally louder and has more vibrations than before. I mean even with the broken transmission mount the car was way smoother than now. I'm going to go back eventually to have this looked at but just wondering what could this be?

The car has a bit of mileage but is doing well mechanically: Mazda 3 with almost 284,000 miles. The spark plugs and air filter have been changed recently.

I'd appreciate your help.

I cant feel it so I have to guess, if they didn't leave anything disconnected it could be the new mount is transmitting more vibration than the worn out/broken old one, this is normal to some degree.
The other thing is depending on if the battery needed to be removed the ECM will need to relearn if a memory saver was not used. This can take some time, not very long but more than a few miles.

If it runs generally good with no CEL then run it a bit longer to see if it improves.
 
The mounts might be binding. They may need to perform the neutralization procedure.
Since the work was performed at a dealership, I assume that a Genuine Mazda mount was used. But if not, that is your problem.
 
Boomer, that's something to look for. Will mention it.

Trav, that makes sense - that the mount actually transmits the actual feeling. I think the battery was was disconnected but I've put many miles since then. It generally runs well and feels smoother while driving; it's just the idle that's more noticeable.

The Critic, it was done at the Mazda dealership so I would assume that the genuine Mazda part was used. I will have them look at it next time I go. The car runs good but I'm not a fan of louder and coarser noise so I'd want to fix it.
 
You might try cleaning the throttle body. I've seen it more than once when a vehicle has the battery disconnected for a long repair that it has running issues later. The pcm adapts to the carbon build up over time but when it's reset it expects everything to be in like new condition.

I've fixed multiple 5.4 3v f150/Expeditions that would die while driving after a plug change either at home or at an independent shop with a simple cleaning.
 
  • Like
Reactions: JC1
Did they disconnect the battery during the service? Driving it for a while will have the computer relearn.
 
I’d go with the idle relearn. I recently replaced my battery and immediately noticed a rough idle while in Park. After 4 days, it’s now idling smooth.
 
Drive it hard ?
I don't want anyone driving mine hard, I would have a problem with that statement.
 
200K miles and you taking it to a dealer for service? They probably disabled your PCV system to cause sludge.
 
What's there to "learn" when the car is idling?

If not happy, take it back and tell them to fix it or you will contact Mazda Corp.

Different issues but i did that with a Toyota dealer couple of times and problem solved ... some dealers think they can get away with it but you need to remind them that you paid more than going to average mechanic and expect more.
 
Back
Top