Help with Mother-In -Law car problem.......

[DAYLEY/CHALLENGER]

She has a 2002 Buick Regal......3800 V6 .  Just started cutting off when slowing down for no reason.  Doesn't do it all the time.....Scared to drive it now and its at the shop.......They are scratching their heads too.......Dash lights come on when it dies.... just like you have just truned the switch on to start.  Today the mechanic had it quit on him and wouldn't start for 45 min.  ???Any sugestions will help.   Thanks.......David

[72rtchallenger]

She has a 2002 Buick Regal......3800 V6 .  Just started cutting off when slowing down for no reason.  Doesn't do it all the time.....Scared to drive it now and its at the shop.......They are scratching their heads too.......Dash lights come on when it dies.... just like you have just truned the switch on to start.  Today the mechanic had it quit on him and wouldn't start for 45 min.  ???Any sugestions will help.   Thanks.......David

possible ignition switch ,,maybe or any number of relays or sensors,,i have even seen the fuel pump cause this problem,,a friend of mine had his car shutting down an start later,he replaced the crank sensor but then it happened again,so when i looked at it the car had just died and i checked for spark and gas,,no gas, took out his fuel pump and found the the pump had come loose internally were the pump separates from the sending unit part ,,i snapped it back together an problem solved,, Also the mass air flow or crankshaft position  sensors may fail causing the engine to stall intermittently.

[Rare_T_A]

I had a Chevy pickup years ago that did that. It turned out to be the fuel pump in the tank. It happened to my daughters Blazer also.   

[rallye73]

GM has done a good job of keeping Airtex and other fuel pump companies going. Go to Autozone and get the fuel pressure tester they have on their loaner tool program. Hook it up and see if the pressure is where it should be. Pump could be getting hot and laying down.

[CHL2T]

My buddies 97? grand am was doing some weird stuff like that and it turned out to be of all things, a loose positive battery cable.
It's always the simplest thing that you check last, trust me I know 

[70_challenger]

David:
Hard to tell without being there to diagnose the car - Could be any number of things.  If I understood your comments correctly, you are saying that all the dash lights come on, like the test sequence when you start the car?  That is a HUGE clue, and would seem to indicate that it is completely losing the electrical circuit momentarily, and then coming back 'alive'. 

My wife's 2001 Camaro (also a 3800) used to do something very similar.  I ended up finding that the main ground wire to the engine block was corroded (along with almost every other wire and terminal on that car!)  It took some work with a volt/ohm meter, but I found several flaky connections at the main power block, due to corrosion.  So I removed and cleaned every terminal in/out of the main power block, as well as every ground wire/terminal I could find.  Of course, I put on a little dielectric grease after cleaning each one.  The key is to catch it when the problem happens!

Best of luck to you.  By the way...when I read the title of your post, I did not see the word 'car'...gives the title a completely different meaning!   

-Tom

[DAYLEY/CHALLENGER]

Thanks guys.........So far the connections  have all checked out.  The mech. also unhooked  some module and it still did it.  I was thinking the same thing on electrical as it does act like all juice is cut off and then turned right back on.  Yesterday it quit on the mech. and wouldn't start for 45 min.   I am leaning toward the fuel delivery.  I will let you know as soon as we figure all this out.   Thanks again........and I do have a good Mother In Law.......

[Supercuda]

If it is at a good shop, and is baffling the mechanic there, it is likely not the fuel system. Many of tese GM cars hve a stacked positive connection at the battery, with TWO positive cables attaching wth a spacer between them. Check for corrosion here, as well as a bad cable. This is a very common problem, and often goes undiagnosed. Cars with lots of accessories are the worst-affected.

[BIGSHCLUNK]

stay away from Airtex ... go w the OEM pump if you can (if needed that is)   

[CHL2T]

If it is at a good shop, and is baffling the mechanic there, it is likely not the fuel system. Many of tese GM cars hve a stacked positive connection at the battery, with TWO positive cables attaching wth a spacer between them. Check for corrosion here, as well as a bad cable. This is a very common problem, and often goes undiagnosed. Cars with lots of accessories are the worst-affected.

Didn't I post the same thing above??
LOL

[MOPAR FANATIC]

  dave,have your mechaic try an ignition module.part#12617924
or ac delco#D1977A List price is 360.50 or wholesale around 252.00/these 3800 are known for these going out and hopefully he can get his hands on one to try.next thing on the list would be a crank sensor pt#10456161
list for 72.00 wholesale 51.00.have him try this 1st.remove the ign module from the mounting bracket,clean off both aluminum mounting surfaces,probably has white corosine on them,lightly sand both surfaces,then lightly coat the surface's with die eletric grease.had this problem with my 3800 park ave and did the above and never had another problem.if that doesn't work try a new IGNITION module next. 

  and good luck 

[Road_Runner]

My wife's 97 Grand Prix with the 3800 V6 had the crank sensor go out 3 times before she sold it.  Definitely worth looking into.  One main difference though was when the sensor went out on hers there was no starting it again until the sensor was replaced so I don't know if yours just fails intermittently or if that means its something else.  Good luck, diagnosing older cars with all the electronics is just a nightmare.  Gotta make you think about all these steer, accelerate, brake by wire cars being built today what they're going to be like in 10-15 years! 

Later, Jim

[Cooter]

I've also seen where a seeping Water pump leaks down onto the crank sensor behind the Balancer and causes it to read irratically....Really need to hook up a scanner to it and wait for the intermittent problem to show itself and see if it has RPM showing when cranking....

[Andrew]

Agree with the Crank angle sensor, A good way of diagnosing this is to carry a bottle of water in the car with you, next time it dies, pour the water over the front of the engine, trying to get as much as you can behind the crank pulley. If it starts, then its your CAS. The reason being, when these are getting dodgy they tend to fail when they get hot, hence the reason the car will die while being driven but start again after 40 minutes.

Im not sure how much applies to US models though. I have a buick 3800 and an ecotec 3800 in aussie RWD holdens. We get different intake manifolds and a handfull of other bits and pieces, but they are still basically the same engine.

[Supercuda]

The "all instrment lights on" clue tells me that it is NOT the CKP sensor. Yes, HANDM, it sounds a lot like what you suggested, but I tried to send him in a direction that most people don't go to in their search for bad connections. This very problem, as I've described, has caught many good mechanics with their pants around their ankles. Very seldom does anybody think of the positive cable as having a bad contact INSIDE of it.