Why won’t my car start after sitting idle for a few days?

Q. If my Ford Taurus sits for three or four days it will not start. If I get a jump start it fires right up. My battery and starter were fine and everything else tested okay. Could it be a sensor or fuel pump?

A. If the car starts with a jump and the battery is fully charged, I would look for an electrical problem. On some Ford vehicles the battery ground cable has been known to cause intermittent no-start problems. A technician with a voltmeter will perform a “voltage-drop” test to determine the cause of your car’s intermittent no-start problem. If you cannot get the car to a garage, look for dirty or corroded connections. Start with the battery and work as far as you can, cleaning along the way. 

Q. I have a 2018 Acura RDX with only 29,000 miles. When applying the brakes there is a thumping sound from the right front. I checked the tire and there is no visible damage. The brake rotor also looks okay. The warranty has long expired. What could be wrong? 

A. A thumping sound is typically a loose component or an out-of-round brake rotor. The issue could be a loose caliper mount, a pad moving, or even a suspension part. At this point, the only thing to do is take the car to a repair shop, demonstrate the problem, and have them perform an inspection of the braking and suspension system.

Q. I added about a half-gallon of blue window washer fluid to my coolant by mistake a couple of days ago. This is a new car to me (I have had it for six months) and I feel like an idiot. Did I do any damage? Do I need to have the system flushed and new antifreeze added or is it okay to leave it as is?                                                                         

A. This is actually a fairly common occurrence – you are not an idiot. Window washer fluid is mostly alcohol and water so there shouldn’t be any engine harm. What I would be more concerned about is that you needed to add that much fluid to the engine cooling system in only six months. You should have the cooling system checked for a possible leak.  

Q. I recently purchased a five-year-old Lexus and took it to my own mechanic to have it checked after I bought it. When she scanned the computer, she found a dozen fault codes. Now the car ran great, and the check engine light was off. When I went back to the dealer, they checked it over and replaced the battery. Could the battery really be causing all those codes? 

A. A good battery is critical to the proper operation of newer cars. Battery voltage that is low or varying can cause all kinds of mischief with computer-controlled systems. My suggestion is drive the car for a couple of hundred miles and then rescan the computer. 

Q. I have heard you mention WORX tools on your radio program, are they really any good? 

A. I have several WORX tools, from a weed trimmer and leaf blower to an impact wrench and light-duty angle grinder, and have been quite happy with the overall performance. One reason I like them is they all share the same 20-volt battery. So, the chances of always having a fully charged battery are quite good. 

Q. I just inherited a 2014 Honda CR-V with only 52,000 miles. When I am accelerating normally from 25 mph to around 40 mph, sometimes I feel the engine bogging down and have this shuddering/vibration. Other times the car runs great. Since the car did not cost me anything I am willing to put money into it. Is this a known issue and what can I do to fix it?

A. If the engine is running properly, I would be looking at a possible transmission issue. Honda did issue a technical service bulletin (not a recall or warranty extension) with a computer update and transmission fluid replacement. In some cases, the transmission may need to be replaced. I would try changing the transmission fluid (use only Honda fluid). In many cases this cures this symptom.

John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE-certified master technician. E-mail your Car Doctor question to [email protected]. Listen to the Car Doctor podcast at johnfpaul.podbean.com.