What would cause my car to act this way?
T., via email.
Dr Gizmo says...
It is great that you have a technician who is trying to save you a few bucks. Since the check engine light is not shining, it is difficult to determine a fault. When the check engine light is illuminated a computer stores clues as to what might be causing a malfunction. When the light does not shine, a technician has little evidence to use in his search for a fault.
Be this as it may, a dirty fuel filter, failing fuel pump or failing fuel pressure regulator might cause the trouble. In some instances, troubles such as you describe might be caused by a faulty solenoid on the camshaft that adjusts camshaft timing.
Ask a technician to consider these as possible causes the next time you stop by your repair shop.
Faulty Connection Causes Diesel Engine To Misfire
My 2006 Dodge Ram with a 5.9-liter diesel engine misfires and the check light is on. I took the truck to a local shop where a mechanic did some tests but he is at a loss. He says he does not know why one cylinder is misfiring. He has checked the compression and the fuel injector. Everything checks fine.
What do you suggest?
O.C., via email.
Dr Gizmo says...Perhaps the cylinder wants some quality vacation time. All kidding aside, if the injector in the cylinder that is misfiring is fine but it is not working it is likely that there is a problem in the wiring to the injector. There may be a loose or corroded connection. Perhaps a ground connection is impaired by corrosion or is loose. Maybe the powertrain control module connection has a fault.
Ask your favorite technician to look beyond the fuel injector and consider my suggestions in his search for the fault.
Blockage Or Defect Hinders HeaterThe heater in my 2000 Cadillac DeVille does not get hot. The blower works fine. Air blows normally from the dash vents, floor and defroster with each setting on the control. It just does not provide heat.
I took the car to my dealership where a mechanic ran some tests. He says that nothing is wrong, but obviously there is. Less than a year ago, my dealer replaced the heater core so I know that is not the trouble.Whats wrong?
F.S., via email.
Dr Gizmo says...
Do not rule out a problem in the heater core. Hot engine coolant must flow freely through the heater core for hot air to blow into the cabin. If something is blocking flow such as rust deposits or even silicon sealer from a previous repair, coolant will not flow through the core to heat the passenger compartment.
Tests performed by the technician probably verified that the control module, diverter door motors and other electronics are working as designed. Now he should consider a check of coolant flow. If my hunch is right, he will find blockage in the heater core or an associated part is causing this condition.
You mentioned that it has been less than a year since the heater core was replaced. If there is a defect in the heater core, the repair might be covered by a 12 month/12,000 mile warranty. If so, you might not have to shell out a penny for this repair.