What happened with my 1997 Chevy Malibu V6?

Question

It was idling and accelerating rough. Fuel injector cleaner didn't do the trick so I took it to a Midas for a diagnostic (check engine light was on). They diagnosed it as bad compression in one of the cylinders. As I didn't want to put the money into having it fixed I've been driving it around for two months looking at new vehicles. So what happens? Car starts running fine. No hesitation, smooth idle. Is it possible that it was a clogged injector that worked itself out? Regardless, what's my recourse to Midas. I'm pretty sure cylinders don't fix themselves. Any input would be greatly appreciated.

Answer 1

It's possible it was anything. More than likely it's a clogged EGR valve, this will cause a car to idle and accelerate rough. Sounds like Midas was taking you for the run around (quick, act surprised!).

Your recourse to them? Not much really...you can ask for a refund on the diagnostics but chances are you'll get denied. If you want to put some effort in you can go above the managers head directly to the local franchise owner or the corporate office. Even then they will try and give you a "credit" for any repair you need done in the future.

The best step to take next is to have the ECU scanned yourself. Take it to a local auto parts store (autozone, o'reilly, etc) and ask them to "pull the codes" for you. Most of them do this at no charge and generate a listing of any codes stored, where they originated from, and what's necessary to repair them. Even if the check engine light has gone off (I doubt it has) the codes are still stored. This will give you peace of mind and ammo against Midas to get your diagnostic fee back (if it doesn't come back with low cylinder pressure).

Low pressure if usually caused by failing piston rings (you'd be burning oil) or a cracked head/bad head gasket (you'd have oil in your coolant, coolant in your oil).

It is possible you had a "stuck" valve that has since worked itself free. It wouldn't be a bad idea to run some motor flush through the engine on the next oil change ($5 a bottle, basically detergent for the inside of your engine)....simply follow the instructions and watch the black sludge drain from your engine afterwards.

Hope this helps!

Answer 2

If they diagnosed it as poor compression in one cylinder, they apparently did a compression test. If there was large carbon build up on one of the valves of that cylinder, it would well have kept the valve from seating properly (sticking) which would in turn cause a loss of compression. In time, the carbon got knocked off in some way or another, the valve seats, and the compression returned.

Recourse to Midas? None really, the only way to give you an error free, pinpoint diagnosis of the underlying problem, would have been to dismantle the engine, and look, costing you far more than you paid them.

If they did not do a compression test, then yes, it could well have been a partially clogged injector that worked itself out.

The best recourse to Midas would be to not return there, find yourself another mechanic/shop that you trust, and use them.

Answer 3

It could have been a wide range of things, too many to guess without knowing what code the check engine light was on for.
Usually a fuel injector doesn't fix itself. As far as what recourse, legally not much.

Answer 4

I would take your receipt back to the midas and talk to the manager, tell him it was diagnosed as a bad cylinder and you havent put any parts on the car and now its running fine. Then request a refund for improper diagnosis, if that gets you nowhere call their corporate office and tell them what happened

Answer 5

At least you learned the "MIDAS" lesson without being ripped off too badly. Most others aren't so lucky.

Answer 6

It's a sign to take that p.o.s into the dealer and trade it in now, before it starts again. Then your old problem is now there new problem