2008 Lacrosse 3.8L Stalls only P0171 code

[jerryls]

I have about only 70K miles and the car ran perfect, then one day I left my house drove about a block and the car died and wouldn't start. The next morning it started but runs really rough. The only code I get is an occasional P0171 which I think is lean fuel. What should I check fuel pump, MAF?
Thanks

[Tech II]

Check fuel pressure....check for a vac leak.....see if vehicle starts with MAF sensor disconnected....

[jerryls]

Originally Posted by Tech II

Check fuel pressure....check for a vac leak.....see if vehicle starts with MAF sensor disconnected....

Thanks- i'll try disconencting the MAF sensor. How difficult is it to check fuel pressure? I cant imagine a vacuum leak as the car isn't that old but I'll check if I see anything.I have a vac gauge. I would think replacing the fuel pump is not an easy job.

[maxwedge]

Check the fp at the injector rail, there is a port clearly visible.

[jerryls]

What should the fp be? Also, if low, does it mean bad fuel pump? I dont think this car has a filter other then an element. type.

[jerryls]

I checked the fuel pressure and its good, holds at about 60psi. Now I get a CEL light and the code is P0300(random misfire). Disconnected the Maf connector and no change in running. It runs but terribe. Could it be a bad coil or ignition module?

[Orlando26]

So do u know what turned out to be the problem, I have a 2007 buick lacrosse and did the same exact thing earlier this week

[Tech II]

Is your's stalling, or like the previous poster, misfiring?

[jerryls]

I thought I posted the results here, but just saw I had not. It turned out to be the ignition control module . Its the flat module about an inch thick that sits under the three ignition coils. using a timing light on each wire I checked the spark to each cylinder and I saw that two cylinders had no spark. Each of the 3 coils generates a spark for two cylinders. The IC module genertaes the primary pulse for each coil and that was missing. I bought a new ICM frrom Herko International for $36 on ebay and the car runs perfect. It was an easy change, one connector and a few screws holding it down. It took less then 15 minutes to change. I took off the plug wires, but not sure if I needed to do that. If you do make sure you mark each one as to where they go.