INGOers with Car Smarts...I need you

[indytechnerd]

Squirrel-ly problem with my wife's car, '04 Mazda MPV w/ 3.0L, 140k miles. It'll just randomly die while going down the road.

No CEL, rough idle, or starting problems. Twice in the last week and probably ten times in the last year, it will die while driving. Never during acceleration, only during steady throttle or coasting, usually coasting/braking, either into a turn or to a stop sign. Doesn't seem to be any common threads between occurrences. We're just now approaching 140k miles, and we've replaced 4 of the 6 ignition coils since we got it in 2008. Restarting is as simple as putting the car in neutral, turning the key off, and restarting. Put it back in drive and go. There's no sputtering either, just quits.

Thoughts?

 

[slowman87]

Weird fuel pump/connection problem?

 

[JokerGirl]

Could be a lot of things...

Some easy and cheap checks/fixes:

Check all of your vacuum lines to make sure they aren't cracked and leaking
Change your PCV valve (This fixed the problem in my car)
Check and sand your electrical grounds
Could be an alternator problem.

 

[Bigtanker]

If it just quits like you shut the key off, my guess is the coil pickup/ crank sensor. If is spits and sputters, fuel delivery problem. Could be the ECM also.

 

[meyer4589]

Check your vacuum lines. My car would stumble like this and die every now and then. Eventually the bad vacuum lines gave me a rough idle and caused the car to die out more frequently till I had the bad lines replaced.

 

[Mark-DuCo]

Sounds like a coil pack problem, I would assume it it were a sensor going bad it would throw a code causing the check engine light to come on but you said it isn't. Could be the ECM as stated earlier, one of my buddies had an pontiac aztec that did this exact same thing and it was his ECM.

If you were a little closer I'd be happy to take a look and hook it up to my scanner and check some voltages.

 

[GLOCKMAN23C]

I would lean towards the crank sensor. Does it have any theft deterrent system, chip in key, or the like?

 

[Mr. Habib]

My wife's car did this last summer. Would start and run fine and then sometimes die without warning at idle or making a slow turn. Never set the CEL. Turned out to be a bad EGR valve and solenoid sometimes causing a very lean condition at idle.

 

[92ThoStro]

Vacuum lines is a good start.

Could be a lot of things...

Some easy and cheap checks/fixes:

Check all of your vacuum lines to make sure they aren't cracked and leaking
Change your PCV valve (This fixed the problem in my car)
Check and sand your electrical grounds
Could be an alternator problem.

You don't even need a PCV valve hose, just take it off and place a breather over it.
Instead of checking your electrical grounds, upgrade them. Make sure to sand the paint.
4AWG from fuse box to battery.
1/0 from battery to ground at strut right.
1/0 fused from alt to battery
Chassis to frame 1/0
Engine block to strut left 1/0

 

[long coat]

How much junk is hanging on the key chain? That has been know to shut off the motor.

 

[74J10]

Another vote for crank sensor on it's way out. They will be intermittent before fully failing.

 

[SEIndSAM]

My Ex had an 06 Dodge Stratus that did the same thing. Turned out to be the computer box. Replaced that and it never happened again.

 

[A_Brit_In_Indy]

Crank shaft position sensor I'd say BUT that only happens when the engine is hot, does it restart straight away or do you have to wait 20 mins or so?
It could also be fuel pump and/or fuel pump relay, and as someone else has said it could be the transponder in the key losing communication with the immobilizer.
PM me if you need more help

 

[slowG]

Maybe a ground for PCM

 

[RobbyMaQ]

I have an 03 mpv, and would have suggested looking at the problematic coils. though usually they cause a little kicking/bucking. Hopefully the 2 you haven't replaced are up front. As you know, the problems usually occur when its damp/wet. However, Are your symptoms occurring during wet weather/driving? or also during dry road conditions?

 

[treeman22]

+1 for vacuum lines. A friend had a brand new ford that would die just going down the road. Took it to the dealership, and turns out it was just a simple vacuum line problem. I would start there first.

 

[indytechnerd]

How much junk is hanging on the key chain? That has been know to shut off the motor.

Nada, 3 kroger type cards and the keyfob. She's not a keychain kinda person.

Crank shaft position sensor I'd say BUT that only happens when the engine is hot, does it restart straight away or do you have to wait 20 mins or so?
It could also be fuel pump and/or fuel pump relay, and as someone else has said it could be the transponder in the key losing communication with the immobilizer.
PM me if you need more help

Restarts immediately, no issue at all.

I have an 03 mpv, and would have suggested looking at the problematic coils. though usually they cause a little kicking/bucking. Hopefully the 2 you haven't replaced are up front. As you know, the problems usually occur when its damp/wet. However, Are your symptoms occurring during wet weather/driving? or also during dry road conditions?

Doesn't matter the weather conditions, wet, dry, hot, cold.

 

[92ThoStro]

check the brakebooster vacuum line

 

[cbseniour]

I don't lknow Maxda that well but I'm thinking electrical possibly a bad connedtion or stator

 

[upalot]

My brothers truck was doing this and after replacing just about everything we found a wire was loose (not on the ends) and would ground out to the exhaust manifold when he turned or hit a bump. The coating on the wire had melted from the exhaust heat.