Car trouble. Dealership scam?

[N80]

And I don't want to come off as bashing all dealerships. As mentioned, our local Nissan place had a bad and well deserved reputation as scammers. I saw them doing dishonest things with one of my vehicles. Recently, they moved to a brand new facility and I've had to deal with them twice about out of warranty issues on my 350z. They found TSBs that I was unaware of on both issues and did major repairs for free....except they did sell me on a fuel injector cleaning....which was my fault....I knew better.

 

[s219]

You can maybe even ignore the CEL if more detailed diagnostics show that the coils are in fact OK. If the coils were failing or on the brink of failing, you sure wouldn't need a CEL to tell you. The car would be bucking and snorting like a rodeo bull.

Sometimes coils can be diagnosed with a resistance meter. Could maybe keep a couple spare coils in the glove box in case one really did fail. I've seen two fail at the same time, but would be surprised if more than that could die together all at once.

 

[Gator6x4]

Most OBD II misfire codes identify the cylinder. Example PO301 indicates a misfire on cylinder one.

 

[RoMad]

we have an 03 Sentra that runs great most of the time but sometimes runs real rough and will barely idle. We took it to an independent shop that i have used and trust. When we took it, it was running fine. They hooked it up and couldn't find anything wrong. The manager told my wife the next time it starts running rough to bring it to him and leave it running so he can try it again. He said sometimes the coils will work and then not. It has been two weeks now and it is running smooth as butter and hasn't acted up again.

 

[N80]

You can maybe even ignore the CEL if more detailed diagnostics show that the coils are in fact OK. If the coils were failing or on the brink of failing, you sure wouldn't need a CEL to tell you. The car would be bucking and snorting like a rodeo bull.

That is what he is going to do. New plugs, premium gas, new air filter and keep driving it as long as it is running smoothly.

 

[94BULLITT]

In most cases the scanner will either tell you what cylinders are missfiring or you will either have a random missfire code. Did they tell him what codes were in it?

 

[sd455dan]

Could be. But this has happened a number of times, for fairly long periods. He does not feel any misfires and no codes from the cat sensor.

I don't know for sure that they were ripping him off but it sure seems that way. In fact, it almost always seems that way these days. And I've had plenty of experience with garages (mostly dealerships) giving my wife the run around but then backing off when I talk with them.

Of course, my son wouldn't be in this pickle if he hadn't dropped out of school and left home. In his defense, he has a steady job with benefits that pays the bills, but just barely. He has never asked for money but I'm not sure he realizes how tenuous his situation is. If the car craps out and he misses a few days of work, he could get fired and then be in a real mess. Sadly, I think many dealerships are willing to take advantage of people in his situation (can't stay employed without a car and don't know enough about cars to cut through the bull and get the right work done at a fair price.)

It seems amazing to me that the ECU in a modern car like his Maxima wouldn't tell you the exact source of a misfire or ignition error. How can this be?

First thing I do when any OBD2 vehicle throws misfire codes for individual cylinders is pull the spark plug on that cylinder.
If it hasn't been changed in 60k or so it gets replaced This has worked on a few rigs i have worked on for friends and family members.
One in particular worked fine for about 3000 miles and started throwing misfire for a different cylinder, at this point changed all remaining plugs -that was over 50 k ago.
All gas 1996 and newer vehicles sold in USA are OBD2 and are capable of identifying an individual cylinder miss. There are codes for random missing also. If the plugs have close to 100k miles i would change them out, it may not take care of the problem but it is not an expensive job to do and who knows maybe it will take care of the problem..


Wooops should have read all the posts first hope the plugs and air filter help...

 

[Coyote machine]

Six coils don't all go at once. If they all went bad at once so would the car's ability to move in any direction.
Missing on a cylinder can be picked up by the onboard computer and not noticeable to the driver.
Dealerships are NOT the place for a car of that age with a kid in charge of getting it fixed. Independent shops with you talking to them on the phone might be better able to help.
All basic items, plugs, fuel filter, air filter are routine maintenance, and need to be done regardless of what else is going on.
Once those are done by a qualified tech then drive it for a while. If the symptoms return then do more.
And no- the cpu's don't always tell the mechanic what to do or replace- unfortunately it's just not that simple, even though it ought to be.

 

[Midniteoyl]

My son lives in Iowa....1000 miles from me. He has a 2000 Nissan Maxima (only 100k or so miles) that is throwing CEL codes that indicate misfires due to a bad coil. This has happened before and usually the coil gets replaced and the CEL goes off. Six months later the light comes on again, same problem. I sent him some money to just take it to the local Nissan dealership and get if fixed once and for all.

According to my son (who knows less than I do about cars) the dealership told him that all the coils tested normal but that the diagnostic said all cylinders were misfiring and the algorithm indicated replacing all six coils and it would cost $1000.

I told him to decline the work, pay the diagnostic fee and go elsewhere. He was told that they had already replaced some of the coils before they told him the cost. He told them to remove them and paid the diagnostic fee of $100 (it is $80 at the dealership here). Then they refused to give him the itemized bill with the diagnostic on it. He made a fuss and they gave him a copy.

My question: Did we screw up or was he getting scammed?

It just did not sound right to me. Why replace coils that test okay? If the coils are okay shouldn't they be checking further upstream in the ignition system?

Mazda Dealer did the same to my brother.. $900 for ONE coil change out. He said 'No' and bought a $120 coil that did fix it.. for a week. Called me and I told him to change the plugs.. Fixed for good :thumbsup:

 

[scrappy isb67]

Thanks guys. Most of the chain auto parts stores will read a code for you for free. He did that and it indicated misfire due to bad coil. It just doesn't tell you which one. I would have expected Nissan's diagnostic computers to tell you which coil but I don't really know what I'm talking about. As mentioned, coils are not that expensive and if he were home I'd buy them and replace them myself.

And I do think the coils attach right to the plug, but not sure.

What I don't understand is why misfires aren't more noticeable. When water got in the distributer cap of my '76 Jeep Cherokee (the absolute nadir of American manufacturing quality) it would backfire loud enough to scare the dickens out of you. Why doesn't his car backfire if it is misfiring and sending unburned fuel through the exhaust? Or maybe it auto-ignites?

There are 2 types of misfire codes, random misfire and specific cylinder misfires. it WILL tell which cylinder is misfiring of a coil is bad, one way to verify the coil is to move it to a different cylinder and see if the misfire moves. if it does then you know the coil is bad. random misfires are much more difficult to diagnose, they can be worn out plugs, bad gas, a vacuum leak, or even a weak fuel pump. if it is sitting around 100K miles, I woult change out the plugs, change the filters and run a good fuel injector cleaner thru it and see if it goes away. the computer is ALOT more sensitive to misfire than your "knock detector" so even if it is not backfiring, it CAN be misfiring and the computer WILL detect it.