2000 Buick Lesabre 3.8L service engine soon. New cam sensor wiring checked reset codes. Light came back on and was told may be crank sensor or the pcm. I am at a loss. The car is harder to start and idles rough no stalling and hesitates some.
Question = what should be checked first service engine light cam sensor was bad replaced with ac Delco light came back on with in 10 miles took it back was told crank sensor may be bad or may have a bad pcm. He wasn't sure and didn't want to spend my money. The car is harder to start at times. It was dead once on third attempt to start it started right up rough idle. Not as much pep. Also the door locks will lock and unlock at times for no reason while in park idling. Where would be a good place to start?
Answer: There are a couple things you can check out. First off, the 3.8 liter engines are known for bad fuel pressure regulators. The diaphragm inside it breaks and fuel gets sucked into the intake through the vacuum line. This creates a hard starting condition due to too much fuel being introduced in the intake. This is an easy check. Get the car hot, preferably after driving a while. Remove the plastic engine cover and you can see the fuel pressure regulator on the fuel rail. Remove the vacuum line that goes to it and let it sit a few minutes. If you see gas start to leak out the hole of the regulator, you know it is bad. Even if you can just smell gas, I would recommend replacing it.
Another thing to check out, and that is known to cause problems like the one your having, would be the Mass Airflow Sensor. You can tap on it while the car is running and see if it stumbles or dies, or better yet, if you can get the car to act up, unplug the sensor and see if anything changes.
I wouldn't be too sure about the crank sensor, when they are faulty it will usually cause a stalling condition when hot, and you don't seem to have that issue. If all else fails, I would check fuel pressure and possibly scan for any trouble codes and go from there.
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