Engine Surge & Not Returning To Idle When Slowing Down

have you run it in to the local mazda dealer to ask them could it be an oxygen sensor problem perhapsis the car serviced regularly.

My car is doing the exact same thing. Have you been able to fix it, if so, what was done?

There is a new update for your computer. I just had it done on my Mazda6 v6. I'm not sure if it applies to the I4 model. Best thing to do is to have it scanned and diagnosed for problem codes. Many codes will not set off a check engine light but will be stored.

my car is doing the exact same thing....i mean exactly as you describe! Have you found out what was wrong with it? mine just started and I havent taken it into the mechanic just yet. if you could give me any kinds of heads up i would really appreciate and I hope that your problem was resolved. Thanks!

Sorry for the late reply -- I don't check email very often. Anyway, yes, the problem was easily fixed. The Mazda dealer updated the power control module. Basically, the computer program that controls the engine and transmission somehow gets corrupted. By updating it to the latest version, the problem is taken care of. The service manager told me they always update it anytime someone brings a car in to be serviced. The problem happened over a year ago and has never recurred. Good luck.

I just bought a 05 madza 6I and it was doing that it could be the igntion switch causing to much spark or not enough spark. have you replaced the ignition coils and spark plugs recently, also could be bad injectors also.

Our 2003 Mazda 6 idles horrible at start up. RPMs surge up and down but after about 1-2 minutes it runs perfect. We have replaced the fuel censor and throttle body and tried to replace the PCV but couldn't get it off. Someone above mentioned having them update the power control module. Anyone have info that could help, or know how much that might cost? Thanks!

Mine did the awful idle at start up and then ran perfectly after a few minutes and it ended up being from a split in the hose that goes to the PCV. I guess once the car warmed up the split would seal itself and that is why it would return to normal idle. In my experience, nothing comes off a 2003 Mazda 6 easily....

Am facing lots of problems with my Mazda6 2003 4cylinders, my car gear always take 3 to 5 minutes before it gets load especially when the engine is cold and I've changed the Gear Box, Brain box, fuel pump, and injector mouth but still the car is not yet okay, moreover, I've scanned it but the scanning machine didn't detect any fault concerning the gear problems please if There's anybody that knows the solution to my problems please don't hesitate to give me the useful informations. Thanks

Just did the pcm update and now the surging rpm is even worse than it was before. New pcv valve. Fresh tune up. Plugs are great. New coils, its quite frustrating. Im at a loss as to its cause. Happens extremely frequent now when breaking between 45-70. Before the update it was only at 45 mph.

I ran a vacuum check on mine I got a 2006 Mazda 5 2.3 and the vacuum ran at 22 lb but it kind of stalls out a little bit especially when you put gas in it just when you put it in it and after a little while it'll straighten out going to come to a stop sign it idle fluctuates they're saying it's the purge unit back by the gas tank which is a hundred fifty bucks 139 if you go to Geek Parts Geek Auto Parts online mine's not real bad but it dies sometimes and I mean that's not revving up and going crazy but it still bothers me I think it might be the purge unit but by the gas tank

Every time we have to replace a battery in this car, this happens. It's computer related!