CX-5 momentarily loosing speed
 

My CX-5 has started slowing down randomly but only for a moment. It feels like someone is tapping the brakes but just for a second most of the time.

Symptoms include:

• No warning lights on the dashboard, wailing of impending failure, etc.
• It's only for a split second. It's happening fast enough that I can feel it but I can't see any change in engine RPM or speed.
• Happens in automatic or manual mode
• Happens infrequently and no repeatable pattern
• Happens more often if using cruise control
• Seems to stop if I drop 10 - 15 mph from interstate speeds
• On one trip the car lost 15 mph going down hill while using cruise control. I literally put the pedal to the floor and it kept slowing down. Turned off cruise control and speed came back up.
• Under heavy acceleration in automatic and then leveling off in speed the transmission won't drop into top gear. Have to go to manual and put it there to drop engine RPM.
• Still under warranty. Yay! :-)

Unfortunately, where I live there are no Mazda dealers. It's 2 to 3 hours one way to a dealer. Trying to figure this out without toasting a day driving round trip plus time in the shop.

Along with this, anyone have any suggestions as to good OBDII diagnostic hardware / software to pick up? I'd like to get some data on what is happening.

Any thoughts as to what may be the problem? New to the site. Thanks for your time and input.

Thanks.

John

Those are pretty unusual symptoms. I've never seen anything like that and I've been on this and another (far more active) forum for years. I can appreciate your dilemma with the distance to/from your nearest Mazda dealer, but in all likelihood, you're going to have to make the journey to have the repairs made anyway. Any simple code reader will give you a basic read on ECU error codes which will give you a heads up on what might be happening. But keep in mind that these codes don't tell you exactly what the problem is; only what system is being affected by the glitch.

This sounds like a problem I had for a while with my Grand Cherokee, but that was the accident avoidance system acting up. I don't think the limited system in the GT with the tech package would act like this, assuming you have that, but it would be one area to check out.

I'm experiencing this with a brand new (200km) 2016.5 auto. I think it's the transmission down shifting or going in and out of gear. Feels like something is resisting when I coast (foot off gas).