Q: I have a 1999 Silverado V8 with just over 100,000 miles. The initial start while cold is usually fine, but after warming up, the truck has trouble turning over unless I depress the gas pedal. I also get a smell of gasoline and seem to be burning more fuel than usual. Also, sometimes when sitting in traffic, in gear or in park, the truck will just shut down. The truck runs fine otherwise and is in good shape. Can you help?
A: You are describing a fuel leak as your problem. A fuel pressure tester needs to be attached to the fuel rail and see where the fuel pressure goes when you turn the truck off. Most common is the fuel pressure regulator. An easy check would be to pull off the vacuum hose from the fuel pressure regulator and look for the presence of fuel in the vacuum line. By the way, no smoking during the test, OK?
If the hose is not wet with gas, turn the key back on to recharge the fuel line, and try pinching the return line off. That will show if you have a stuck open pressure return valve. If, with the fuel line blocked and no presence of fuel at the regulator, the fuel pressure is still dropping, then you have a leaking fuel injector or fuel injector rail. Removal of the injectors is needed to identify which injector is leaking.
All of the above work can be hazardous, and if you are unfamiliar with the system, you are better off going to a professional, and bring this letter with you.
Q: I currently drive a 2004 Saturn Ion Red Line, which is an Ion with factory supercharger and manual transmission. At random as far as I can tell, the car will not start. It makes a real low hum as if trying to start and flashes a symbol on the dashboard of a car with a lock and also flashes "Service vehicle." I have had a new key made and was told at the dealership that there is no chip in the key. I thought that maybe it was only happening when it was cold or wet outside, but it has started on the first try in those conditions and not started when it's warm and dry. Then it will start every time for weeks, even months, then it will "act up" every time I try to start for a few days, then only once in a while every few days. There is a keyless entry and factory alarm, but it also does the same thing when I leave it completely unlocked after turning it off. Please help. Any information would be great. Thank you.
A: Sounds like you have a marginal ground in the engine. Check all battery connections at the battery, engine, starter and alternator. Check computer grounds, as well. To check all the computer grounds, you will need a printout of the wiring circuit for this car.
Car Care Tip: Now is the time to check your air conditioner and cooling system before shops get overloaded with these types of repairs. You will avoid a long wait to have your car repaired.
Larry Rubenstein is a master technician who owns a North Shore service station. Write him care of the Gloucester Daily Times, 36 Whittemore St., Gloucester, MA 01930, or send email to scan firstname.lastname@example.org.