Mazda Protege shaking/idling problems

[Heddi]

Hi!

I've got a 98 mazda protege, automatic trans. It's been a great little car with no problems whatsoever....until yesterday, that is.

Yesterday afternoon, we changed the battery in the car, and once the new battery was put in, whenever we'd drive the car and come to a stop, the RPM's would go down to 0, the car would shake like it was idling really hard and going to konk out, then the RPM's would go back up and the car would stop shaking.

We put the old battery back in, just to see if the new battery had anything to do with it----still shakes.

This only happens if I'm at a stop light/stop sign---RPM's go down to 0 for about 5 seconds or so, then slowly come back up, and shaking stops. It also shakes moderately if I'm changing from Drive to Reverse, or Reverse to Drive, or Drive to Park, etc etc.

We've got an appt. to take it into a mechanic later this week, but didn't know if there was any kind of at-home-diagnosis we could do in the mean-time (we're sort of mechanically impared, if it matters. Hubby can change spark plugs and tires and battery, but isn't too up-and-up on 'real' car mechanic information)

thanks!

heddi & mark

[link785]

Hmmmmmm, my first thought was, are the battery cables (negative in particular) securely fastened? A lose connection can cause what you're describing.

[BMWilli]

I used to have an old protege that did that, never found out what the problem was....but suspected something to do with idle...or vacuum leak somewhere. I've never had any good experiences with mazda's, don't think i will buy one ever again

[Spoon_r]

try the spark plug wires, that might be the prob.

[BMWilli]

not for mine it wasn't i replaced them with magnecors

[Frankk]

Hi Heddi,

Have you solved your problem yet? I have 97 Mazda Prot¨¦g¨¦ LX, 50000 miles, which has same problem as you described-- idle rough at stop light. Coincidently I noticed problem after I replaced the battery several days ago.

I will take the car to a shop for a tune up, which I have not done for awhile, to see if the problem will go away. I will be grateful if you let me know if you have fixed the problem.

Frank k

[Dirty_SOHC]

I have the same problem in my 98 civic

[1badPT]

It could be a temporary thing. Most ECU's have "soft" memory which means a lot of its operating instructions are stored in memory that gets wiped out if the battery cables are disconnected for some time. Your ECU might be "relearning" that information, and until it does, it will run rough. That's all I can think of, but I had that problem whenever I disconnected the battery on my old Cirrus. Took a couple of days to get back to normal operation. GL

[carmex]

does the car actually stall? If it does, can you start it back up again?


I have the same problem with my 99' Focus, but just when it's cold, pretty much below 20-25 degrees.

[Heddi]

Come to find out, there was a loose hose near the air filter which didn't regulate the amount of air coming into the engine or something...

So all that the mechanic needed to do was just tighten up the hose and all has been good to go

[Dirty_SOHC]

Originally posted by 1badPT
It could be a temporary thing. Most ECU's have "soft" memory which means a lot of its operating instructions are stored in memory that gets wiped out if the battery cables are disconnected for some time. Your ECU might be "relearning" that information, and until it does, it will run rough. That's all I can think of, but I had that problem whenever I disconnected the battery on my old Cirrus. Took a couple of days to get back to normal operation. GL

My problem has been present for over a year now. since I have swaped over from a stock ECU to a older ODBII P28. I've checked all the intake manifold over and no luck..

[Dirty_SOHC]

Originally posted by Heddi
Come to find out, there was a loose hose near the air filter which didn't regulate the amount of air coming into the engine or something...

So all that the mechanic needed to do was just tighten up the hose and all has been good to go

Congrats

[1badPT]

Originally posted by Dirty_SOHC


My problem has been present for over a year now. since I have swaped over from a stock ECU to a older ODBII P28. I've checked all the intake manifold over and no luck..

You might need to do some chip tuning then, especially if its an older ECU since they tend to store a lot more static data - it may not be tuned efficiently for your engine. I dunno what your car is though so I'd check on a car specific forum as to what your options are for adjusting the variables in the ECU, or if its smarter to go with a standalone.

[Dirty_SOHC]

I am currentley running hondata for over a year, the problem hasnt been grave enough to bother me. but I would like to eventually get this resloved. Anyone else have any ideas??

[carmex]

Originally posted by Heddi
Come to find out, there was a loose hose near the air filter which didn't regulate the amount of air coming into the engine or something...

So all that the mechanic needed to do was just tighten up the hose and all has been good to go

Yes I think it is just the intake sensor that needs to be adjusted, like I said mine only does it when it's cold out, usually under 30 degrees, everything on my car right now is stalk, so I gotta take it in.

[Tim K]

Did you ever figure out what the problem was with your idle?
I have the exact same problem with my protege after disconnecting the battery to replace some parts. Rough idle when stopped, especially bad with car in park. Ran well before disconnecting the battery. I read where the ECU does need to reprogram but I've been having problems for roughly a week now.

[l/l/rX]

Originally posted by Tim K
Did you ever figure out what the problem was with your idle?
I have the exact same problem with my protege after disconnecting the battery to replace some parts. Rough idle when stopped, especially bad with car in park. Ran well before disconnecting the battery. I read where the ECU does need to reprogram but I've been having problems for roughly a week now.

read:

Originally posted by Heddi
Come to find out, there was a loose hose near the air filter which didn't regulate the amount of air coming into the engine or something...

So all that the mechanic needed to do was just tighten up the hose and all has been good to go

[Tim K]

Strange coincidence don't you think? I never touched the aircleaner on my car before disconnecting the battery but it can't hurt to check...thanks.