1. CEL (Check engine light) comes on, car had been running rough and jerky, I take it to Mavis and they said it was a cylinder 1 & 2 misfire code. They replace all four coils and spark plugs. I did not authorize any "preventative maintenance" to replace the good cylinders 3 & 4 plugs and coils.
I test drive it and it ran worse than before.
2. I bring it right back, Mavis says it could be things other than coils/plugs. So they spray the Mass Air Filter (or something like that) and start switching coils around, they tell me it is done.
I test drive it and it ran just as poorly.
3. I bring it right back, Mavis says it could be that the some of the new coils might be bad. So they order another set of four coils. By now, they have tried 10 or 12 different coils, trying to find/fix the misfire.
I ask for my original OEM coils, am told they have them, I get there and they cannot find, but says the counterman knows where they are, I come back next day and…they claimed the old OEM coils got sent back to their vendor when they sent back the four new coils they ordered. I don’t think a vendor would take 4 old, 66,000 miles used coils. They would not look new, nor would they match any of the 2 sets of new coils Mavis ordered from them and tried out.
I test drive it and it ran just as poorly.
4. This time, I took the manager along. It clearly ran terribly and he said "that's your transmission, we fixed your misfire." I pressed him back at the shop and he again said, "tranny." So as far as Mavis was concerned at that point, I had a tranny problem and they fixed the problem, even though the car was running worse after they worked on it.
5. During the eight days they had it, I came to learn that they do not have the advanced diagnostic tools to do the job. The guy was using a hand-held scanner like the one I have. The counter guy was looking up my error codes up on Google. They even said they were not a full service shop. On day eight I suggest that they should offer me a refund. No luck.
6. I take it back, drive it a day or two hoping the CEL comes on. It does. I take it to Hyundai. They carefully document and photograph along the way and told me Mavis installed four improper plugs. So all that coil swapping and fiddling was for naught, given it would run poorly with the wrong plugs no matter what. I contact Mavis and suggest I also want Mavis to pay for Hyundai having to undo the work they did - makes sense. No luck.
7. Hyundai installs 4 proper plugs and informs me that the coils on the car are the old, original OEM coils and that one of them is bad. That explains why Mavis could not hand me my old coils. They were on the car. I was charged for 4 incorrect plugs and 4 new coils which I do not have in my possession. I have it in handwriting that the reason my 4 coils were zip tied together by Mavis is because they damaged the 2500.00 wiring harness while they were playing musical chairs with all the coils.
The car runs like a charm now and cost me about 400 at Hyundai, most or all of which Mavis should pay for. Hyundai took HD photographs and documented their repair every step of the way, noting what they found.