Q: My daughter has a 2008 Ford Focus that hesitates and stalls when it is warming up from a cold start. So far I have installed new Motorcraft spark plugs, air filter and fuel filter with no improvement. I took it to a dealer but all they could come up with were some random misfire codes. They said that I would need to install a software update for $149. If that does not fix it, they want to do further testing. Why would the car run fine for 65,000 miles and then need a software upgrade to fix this problem?
A: My ALLDATA automotive database pulled up Ford service bulletin 11-8-22, dated August 2011, that describes an idle issue potentially caused by the powertrain control module (PCM) commanding an erratic signal to the exhaust gas recirculation valve (EGR) stepper motor. If diagnostic testing confirms an erratic signal, the bulletin calls for replacement of the PCM.
Before delving into the elusive world of electrons, start with the simple stuff. Hesitation and stalling after a cold start are often caused by a lean fuel/air mixture. Look for any type of intake vacuum leak, positive crankcase ventilation (PCV) valve issue or an air leak downstream of the mass air flow (MAF) sensor.
Check for other causes for a lean condition such as an inaccurate coolant sensor signal or low fuel pressure. And don’t overlook routine maintenance items like the fuel filter (replace every 30,000 miles) and the air filter (replace every 60,000 miles).
Q: I have a 2004 Nissan Altima 3.5 SE with 105,000 kilometers on it. At about 90,000 km, the car started making a clunking noise that seemed to come from the front end. The dealer could not find anything loose but suggested the front struts be changed, which was done. There was little improvement. The clunk seems intermittent and happens at slower speeds when going over bumps. I know there is something wrong somewhere but the Nissan dealer is unable to locate the problem. I’m rather fussy and the car sounds like a piece of junk when the clunking happens.
A: Nissan issued a voluntary recall NTB05-114c, dated June 2012, addressing the possibility of corrosion in the rear sub frame bushings of some 2002-2005 Altimas driven in “salt” environments. Nissan will replace and extend the warranty on the rear sub frame for a total of 13 years and unlimited mileage on the affected vehicles.
Because you live in Canada and the bulletin identifies specific “salt” states in the United States, have your dealer check eligibility if this is the problem with your vehicle. Because you sense the noise coming from the front, have the dealer check the front bushings as well.