Old Dr. Gizmo column

“Dr. Gizmo”

By Phil Arendt

Time To Dig Deeper    

Question 1

My 2010 Mercury Milan Premier with a 3.0 engine and 111,000 miles sometimes cuts out and stalls.  It restarts but sometimes it is difficult to restart.  The trouble has been going on for over a month.

I took it to a shop that’s been servicing our family cars for many years.  They have performed several tests but have not found any computer codes to help find the cause.  They have replaced the crankshaft sensor and engine computer to no avail.

I went to a dealership where they did tests and replaced the throttle body.  This did not fix the trouble.

I went back to my local shop, but after checking everything they can’t find the cause of the trouble.  They have experienced the issue but are at a loss.  Can you help?  M.W., email

Answer 1

This indeed is eluding diagnosis.  The fact no malfunction codes point toward a fault is making it difficult to find the source of trouble.  It’s likely a technician has looked for faulty connections at plugs and for loose or corroded ground wires.  It’s time for a technician to consider inspecting connections in places that are not easily accessible such as conductors and plugs under the intake plenum.  It’s likely he or she will find the source of this aggravating condition in a location not previously probed.

Worn Out Before Its Time

Question 2

The check engine light turned on in my 2008 Toyota Tundra with a 4.7-liter engine.  It has 66,127 miles.  I bought it about two years ago.  When the check engine light turned on I noticed that the engine was running rough.  I took it to a local shop that has been around for a long time and has a good reputation.  They determined the valves were two tight and there are multiple misfire codes.  They replaced the spark plugs and attempted to adjust the valves but the technician found too much wear.  He did a compression test and found four cylinders below specifications.  He determined the engine is in need of replacement or overhaul.  I did not give permission to do the work.

I went to a dealership for a second opinion.  They did a compression test and other tests confirming the first shop’s diagnosis.  They said the problem is excessive wear.  The engine is shot.  I asked them if this is typical of this engine.  They said it’s not and that this engine usually lasts 200,000 miles or more.  They could not tell me why the one in my truck wore out at this low mileage.  Have you ever seen anything like this?  C.L., email

Answer 2

Yes.  It appears that an event such as overheating or lack of lubrication due to a low oil level is a likely cause.  It’s also possible this vehicle was a salvage vehicle from one of the weather catastrophes such as Katrina or Sandy. 

Your dealership is correct.  With reasonable preventive maintenance care this particular engine usually has a service life of 200,000 miles or more.  Now it’s time to decide your next step.  To fix the trouble requires expensive repairs.  Consider all options carefully to fix or dump the vehicle

Air Bags Inoperative

Question 3

The air bag light is on in my 2003 GMC Envoy SLT.  My vehicle has 152,000 miles.  I checked the fuses.  They are fine. 

I’ve owned this vehicle since it was new.  The light for the air bags has never turned on before.  My truck is in great condition.  I’m willing to repair this issue but heard it might cost more than the vehicle is worth.  Is this an expensive repair?  J.M., email

Answer 3

Certainly you need a properly working system to help protect you in a collision.  Right now the air bags will not deploy.

Replacing all of the air bags is an expensive repair but this likely will not cost more than the value of the vehicle.  This issue might be caused by a failed module or perhaps a failed electrical connection in the steering column.

Fuses Hide In Unlikely Places

Question 4

I have a 2009 GMC Canyon SLE with a 2.9-liter engine and 103,000 miles that one morning would not start due to a dead battery.  I jumped the battery but the truck would not start.  I had it towed to a local shop.  They performed several tests.  They found that there is no power to part of the ignition switch.  They say there might be a blown fuse but will need to trace the wiring to find it.  They say it might take several hours to find it.  Also, they say the battery is shot.  

Aren’t all the fuses in a fuse panel?  Does this seem right to you?  R.V.T., email

Answer 4

Not all fuses are in fuse panels.  Vehicles also have inline fuses that are hidden behind interior trim and in harnesses in the engine compartment.  Analyzing wiring schematics will help find the failed fuse.  Probing needs to be accomplished to isolate the ignition switch circuit that has lost power.  Once this is accomplished a schematic should show the approximate location of the failed fuse.  It might be under the dash or hidden behind a panel such as a kick panel. 

Worn Wiring Insulation Stalls Engine

Question 5

My 2005 Pontiac Grand Am SE with a 3.4 engine sometimes hesitates, surges, and cuts out.  Also, the check engine light is on.  This does not happen until I have driven for more than 30 minutes or so.  Also, it only happens when I accelerate aggressively such as when entering a highway or passing.  It does not happen every day.

I went to a local shop and dealership for this issue.  Technicians at both shops experienced the trouble.  Tests at both shops found the circuit to the MAP sensor has a fault but neither shop has determined why.  They say the sensor does not have a fault and the wiring looks good. 

Do you have any suggestions?  A.C.W., email

Answer 5

Yes indeed.  It might be time to say goodbye to your Pontiac.  All kidding aside in 20 years it might qualify as a collectable vehicle.

As for the cause of the trouble, it appears technicians at both shops have done visual exams of conductors within the sensor circuit.  It’s also possible they performed wiggle tests with test equipment connected to the circuit but no issues were found.  Be this as it may, more probing is needed.  It’s likely a wire hidden under a device or component is partially broken or the insulation is worn off.  It’s time for a technician to dig deeper into the circuit in hidden areas where the cause of the condition will be found.

Clunking Sound Eludes Diagnosis

Question 6

I have a 2006 Dodge Charger R/T with a 5.7-liter engine that has a loud clunking sound in the front-end.  My car has 102,000 miles.  Recently, a shop replaced the ball joints, sway bar links and rear shocks.  This shop was far away so I went to a shop close to home.  They drove the car and heard the noise.  They determined the front struts were the cause.  They have never been replaced.  They replaced them but the sound remains.  They say all the work the other shop did looks good.  They don’t know what causes the noise.  They say the car is safe to drive.  Do you have any suggestions?  P.J., email

Answer 6

It’s time to trade your Charger for a Hellcat.  On the other hand 700 horsepower might be a little too much for you to handle.  All joking aside, this issue needs repair.  The noise might be the result of worn engine cradle bushings or loose cradle bolts.  It’s also possible the sound is the result of excessively worn or dry sway bar bushings.  Ask your favorite technician to consider these suggestions the next time your vehicle rolls into a shop.

Thank you for all the great questions.  Dr. Gizmo can’t wait to answer more.

Phil Arendt is a columnist, consultant and A.S.E.-Certified Master Technician.  Readers may send questions to Dr. Gizmo at his e-mail address drgizmo@drgizmo.ws.  02/12/2018 ® DR. GIZMO © 1989 – Present