QuestionDTC was P0300, P0301 and P0392. Tune up "includes" plugs, wires, filters, valves (I assume)etc, plus 2 1/2 hrs labor. He also said that after the tune up, he would be able to determine if coils are necessary but the codes might clear after the tune and coils are not needed. The car starts, drives and reacts "normally".
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I had the car checked and my mechanic stated I may have ignition coil pack probelms. He stated the car had 3 packs and didn't know the cost but before he knows for sure, I need a FULL tune up, soup to nuts setting me back $600. Does this sound right?
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I started the car and it started to feel rough, like when you start a cold engine. Thinking that this was the problem, I warmed the car up. The engine felt like it was smoothing out when the check engine light came on. I shut the engine off, waited and tried again. The light went out and after 30 seconds, it came back on. I shut it off and restarted and light is on. Granted I have less than 1/8 tank and it was sitting in a rain storm for at least 24 hours. What do you recommend?
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You should have your engine and transmission diagnostic trouble codes read. Since the check engine lamp came on in conjunction with the problem, it's likely that the information in the computer will lead you in the direction of the problem.
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It's possible he's right. The question about the coils is a little troubling, though. The coil is easily accessible and should be able to be tested easily. What was the diagnostic trouble code? Without that, I cannot tell you whether his recommendation is consistent with the code.
What's being included in this "full" tune-up? It's hard for me to tell whether everything there is addressing your issue unless I know what's being done.
I will say that replacing the spark plugs and wires on the 2.7 Santa Fe is an expensive proposition. It requires removing the intake plenum to access the rear three plugs and wires.
AnswerSince P0392 doesn't apply to your vehicle, I'm going to presume it's a typo and should be P0302.
P0300, P0301, and P0302 represent misfires. P0301 indicates cylinder #1, and P0302 indicates cylinder #2, while P0300 indicates random or multiple misfires.
The vast majority of misfires are caused by the secondary ignition system (plugs, wires, and coils). On your vehicle, the wires are the single most frequent cause. The fact that you say "the car starts, drives and reacts 'normally'" causes me some concern, however, that you may have a problem that's not related to the ignition system. When a vehicle experiences an ignition misfire, it is typical to feel a vibration and, on acceleration, feel a lack of power.
If you're not noticing a lack of power, I'd suspect you may have a problem with some of your fuel injectors (most notably those on cylinders 1 and 2). Although not with the same frequency as the plugs wires, I've seen injector problems with significant frequency on the 2.5 and 2.7 V6 engines.
Even so, any way you look at it, the repairs won't be cheap. The original plugs are scheduled to be replaced at 60,000 miles. If you've passed that mileage and haven't replaced them, it's time to replace the plugs and wires as maintenance anyway.
If you're going to replace the plugs and wires, it'd be a good idea to take the injector rail loose and visually inspect the injector ends. On most vehicles that experienced misfiring due to injectors, it was possible to see the clogging simply by visually inspecting the delivery end of the injector. It's also a good idea to switch the #4 or #6 injector with the #1 injector. That way, when everything is reassembled, both the suspect injectors will be on the front bank and can be serviced without removing the plenum again. If the misfire follows the injector from cylinder #1 to cylinder #4 or #6 (the new injector location), you'll know that the injector was the cause of the misfire.
I don't understand why the coil cannot be checked before doing the work. Since you don't have misfires that would be attributed to a single coil pack (1 and 4, 2 and 5, or 3 and 6), we already know that the primary ignition system is working. All it would take to check the coil would be to take a known good plug wire, install it on the coil, and put a good spark plug (or spark tester) in the end and lay it on the intake plenum. If the plug (or tester) sparks, then we know the coil is working. We could do this on both coil post #1 and coil post #2 to verify proper coil operation.
Since your misfiring is limited to two cylinders, it shouldn't be caused by filters. I'm not sure what filters are being recommended, but they won't address a misfire that's only occurring on two cylinders. A filter would affect the entire engine, and a failure, if it could cause a misfire, should cause a misfire on all cylinders.
I also don't know what valves would be replaced in a tune-up. A PCV valve, maybe? This, too, if it were to fail and cause a misfire, should cause a misfire on all cylinders on all cylinders, not just two of them.
By the same token, that doesn't mean you shuoldn't replace those items. It's recommended maintenance to replace the fuel filter every 52,500 miles, and the PCV valve every 30,000 miles.
I suppose the thrust here is that the work they've recommended may solve your problem and it may not. I'm not convinced the shop has done any significant diagnosis, but I'm also in no position to make a judgment. Most likely, all the work they've recommended should be done as regular maintenance, but I have reservations that the shop may not have made any direct link between the work they're recommending and the work that's necessary to solve the problem you're having.
