97 that shuts down for a second at a time

[ram2407]

97 V-6 auto 100K has developed a bad habit of periodically shutting down for a moment, long enough to kill the engine if I am not rolling over about 40 mph, just a hiccup if I am traveling faster. Only happens after the car has warmed up, much more likely if it has sat for awhile since the first drive of the day, almost never happens on the first drive. It is like someone just turns the ignition off then back on instantly, usually restarts fairly easily. Dealer has had it several times and not figured it out. Replaced the ignition switch because the radio was going dead periodically (much less often) and we thought the two were related--didn't help. I like this car and want to keep it, but this problem is potentially dangerous, especially when I stall in a line of angry shoppers on their way to the mall.

[ikeyballz]

lol, that doesnt sound too good.. so how does it turn off? it just.. (poof) turns off or..it (shake rattle rattle cough) turn off. ?

if its a smooth off, its usually the electrical system...

if its a hesitant, dying off, its usually the fuel system...

i think you said its like someone turned off the ign, so im guessing its the electrical system...are the spark plugs all good? the rotor? rotor cap? distributor? (hopeflly thats not ur prob..) how about the ign. coil..you can check the resistance on that to see if its bad.. etc etc etc. maybe its a bad ground? if your grounds bad, nothings gonna work at all..also explains your radio dying...

good luck man, sounds like a major electrical gremlin

[ram2407]

if its a smooth off, its usually the electrical system...

if its a hesitant, dying off, its usually the fuel system...

Very quiet and abrupt. I think the behavior eliminates a fuel problem, especially since it restarts so easily.

are the spark plugs all good? the rotor? rotor cap? distributor? (hopeflly thats not ur prob..) how about the ign. coil

That's all been checked, and it runs perfectly in between episodes.

good luck man, sounds like a major electrical gremlin

Thanks. I have had three suggestions, crankshaft position sensor, camshaft position sensor, and coolant temperature sensor. Any thoughts on those three potential culprits?

[GTP Dad]

Actually this sounds like a problem with the PCM/ECM. You may have a bad component in the computer that is causing the shutdown. Since it is so abrupt then something is interrupting the ignition circuit. The computer would do this and since you have not codes it will automatically reset and allow you to start right away. I would check this too.

[CreepingDeath94]

I don't think the temp. sensor would have much of an effect on shutting the engine off abruptly like that...

[ikeyballz]

do you have a spare bird lying around? or know a buddy with one? borrow his ECM. and hook it up to yours..i did that before with my cars... lolz, be careful not to fry his tho! if it works fine i guess thast your prob..i dunno how you would find out any other way.. i dont think it would be sensors..because if it was, why would they cut power to the electrical system? and why would it work/not work/work/notwork so simply? just my 2cents..im not sure...

[ram2407]

I don't know if I'm closing in on the problem or wandering around in circles. Does anyone know exactly how the sensors (coolant temp, crank position, cam position) actually work, whether any are capable of shutting down the engine if they fail, and whether it can happen intermittently? Also, the suggestion that I check the PCM/ECM is a good one, but how do I do that? Is replacing it and seeing if that does the trick the only way? I've already spent a lot of time and money on this problem and if I can't fix it soon, the car will be a planter and I'll be driving a Honda or some other dang abomination. Thanks to everyone so far.

[GTP Dad]

The cam and crank sensor can shut the car down if they malfunction. The temp sensor probably will not other than cause the car to run bad. However, both of the above will shut the car down resulting in a complete stall not the type you describe. Although you may want to change the CKPS and CamPS to see if that corrects the issue. However, this sounds more like a problem with the computer rather than a sensor. Good Luck!

[ram2407]

As an update, I replaced the ECM yesterday, still waiting to see if it took care of the problem or not. This is getting expensive!