'01 Impala 3.8 stalling problem

This is the same car that had a hard starting problem after sitting... seems like there is something else wrong because every once in awhile the engine just decides to quit. The hard starting problem was repaired with a new fuel pump. Starts first crack of the key now. There have been many components replaced and it runs really well when it runs. The parts that have been replaced are the MAF, IAC, CPS, fuel pump, fuel filter, air filter, plugs, wires, PCV, intake and plenum gaskets, lifters, just to name a few. The car went to the shop for a scan last week and they cleared the codes and said to bring it back the next day to get the new codes (there were some false ones) and they said they didn't know what was wrong. I'm starting to suspect a bad ICM but am hesitant to replace it as all the other parts didn't fix the stalling problem. Has anyone else had an Impala that would run so smooth and sweet for several hundred miles and then decide to just quit and not want to start again?

You need to find out what is missing when it stalls (spark or fuel). Once you know what is missing it will be a lot easier to figure out what needs to be fixed.

hey karpman,intermiting problems can be a bitch! in time it will get more constant.ck for dry cracked vacuum hoses.when it stalls ck basics fuel,spark
thats all u can do without guessing??? Good Luck

Thanks guys for the advice... what should I do to check for fuel and spark? Thinking maybe strap a pressure guage to the windshield and an inductive timing light to the dash, because otherwise I can't think of how to check for spark or fuel. The problem is so intermittent that sometimes it will start right back up again and other times it'll just crank and crank and not fire up. Also, sometimes when I try to start, the starter will not even engage. Bad ignition switch maybe? There must be a way to diagnose this without replacing every part. Still thinking bad ignition control module, or bad ignition switch.

OP, mine did... Of course my security light came on (of course this is a PK2) issue) but like mine wouldn't even turn over... could be a bad BCM (just throwing ideas out there)...

Mine doesn't have the security thing... it's an ex-police car. Where is the BCM and the PCM located?

BCM: just above the parking brake pedal. Remove the plastic kick panel, and the BCM is mounted on the sidewall.
PCM: Take the airbox out, and you will find the PCM in the lower half.
My guess is the ignition switch.

Many thanks everyone... on a whim, had the crank sensor replaced again and so far no more stalling problems. Will replace the ignition switch in the future to repair the no crank problem. For now, if I hold the key in the start position, the starter will eventually engage. These were definately two seperate problems and each should have had their own thread but I thought they were both related.

Many thanks everyone... on a whim, had the crank sensor replaced again and so far no more stalling problems. Will replace the ignition switch in the future to repair the no crank problem. For now, if I hold the key in the start position, the starter will eventually engage. These were definately two seperate problems and each should have had their own thread but I thought they were both related.

this starter problem that you believe may be the ignition switch may be the starter solenoid....or just loose wires at the starter....when you go to start listen for solenoid to click when turning key....

the other problem of stalling and then running great with DTC codes not clear is usually this CPS....I have found them to be intermittent in resistance..usually the resistance gets higher than whats the spec...

j Cat, already tightened starter connections at the starter end as well as cleaned the battery terminals, plus new battery. No clicking when the no-start situation occurs. One of my co-workers had the same problem with his Impala and they changed the starter and still would not crank on occasion. I guess I must have the security module in there as I did get a padlock symbol on the message center before... someone already suggested that on an earlier post. Anyway, I drove the car again today for almost 6 hours and no stalling! I'm really happy about that. Also thanks for the suggestion on an earlier thread about the hard starting problem... new fuel pump was bad and tried an AC Delco one next and problem fixed.

Also the CPS is located in a place that has to endure extreme conditions, such as heat, moisture, coolant and oil leaks that could possibly contribute to the lack of longevity of this component. The parts store said they sell these sensors like popcorn. They keep 15 in stock and when they get down to 3 they order more.

with no noises and the lock light on this is most likely your problem now...perhaps this secuity system can be bypassed..

Mine doesn't have the security thing... it's an ex-police car.
I wondered about that..I've never heard of an Impala that didn't have Passlock.
There is a Passlock bypass procedure. Many people here have had good luck with it. I did it on my Alero about 2 years ago, and have had no problems since then.
Here you go:http://www.automotiveforums.com/vbulletin/showthread.php?t=698861&highlight=passlock+bypass

Iflylow, didn't know about passkey11... very interesting! Had a 1994 buick before and the key had a chip in it...must have been the early style. Since there was no chip in my Impala key I just assumed I didn't have vehicle theft deterent. From what I read, the lock cylinder feeds a signal in varying resistances to the BCM, which then determines what signal to send to the PCM to enable or disable the starter relay. Sounds like this bypass method is a good way to fool the BCM into thinking the key is in the ignition. I'm going to get a new key cut first as mine is not the original one and also has been well used. Maybe it doesn't always make a good connection on the part in the lock that feeds the BCM.