Took the wifes 2008 G35X to Firestone today to take advantage of their full synthetic oil change special. The car was running fine before Firestone did the oil change and courtesy inspection. Once I left the car was idling rough jumping between 400-600rpm and it just got worse from there. Started driving the car back to have and it would start to idle really low maybe 200RPM I felt like it was going to die. Brought it back they checked all the usual to see if there was a vacuum leak anywhere on top of the engine. They claim all they did was change the oil and literally just inspect the air filters. After they couldn't see anything on top of the car they put it on the lift and they had me come out to the shop. They told me to feel the extreme heat coming off the catalytic converters. They weren't glowing orange but they were extremely hot and the car wasn't even beat on or driven hard and its 38* outside.

Is it possible they could have popped off a vacuum line while checking the air filters? The boots seemed to be seated nice and tight they didn't see any lines not attached. I let them keep the car they said their master tech would be in tomorrow to diagnose it and they would call me. They did have their scanner hooked up and he was trying to monitor the o2 sensor while the car was running but he said it wasn't getting a reading. He said there were stored codes as well one was a BCM fault, transmission fault, and something else. Her car previous to this was doing a really weird thing while driving the Slip/VDC Off/ABS light would come on randomly while driving. Turn the car off turn back on lights would come back on in a few weeks or sometimes a few months but the car drove fine. I also know that she has a problem where when she washes the car water will sometimes leak into the front passenger door pilar and run down to the glovebox area. The sunroof drain has since been unclogged but could that have done some type of electrical damage?

Either way I just have a hard time believing the car drove to Firestone perfectly fine but after leaving this all instantly happened. Car is a 2008 G35X with 64,000miles. Any help is appreciated so I can return tomorrow to compare what you guys tell me here to their "diagnosis".

 

Sounds like water damage to the IPDM, possibly other components.

I would remove the battery, take the cover off the IPDM fuse box behind it and see if it is wet at all.

Did Firestone give the car a courtesy wash while you were there?

 

Thanks for the reply! No they didn't wash it at all. Car was running fine right up until about two minutes after I left Firestone. What does the IPDM do?

 

I am still extremely confused as to why the Service Engine Soon light didn't even come on at all..

 

IPDM - Intelligent Power Distribution Module. It's basically the engine bay fuse box but it's directly tied to the ECM via CANBUS. ECM tells it to do things like close the starter relay, fuel pump relay, blah blah electrical switching stuff.

You may have also gotten the ECM wet, it's mounted on the outboard side of the right seat (passenger usdm) footwell.

To start with, WHAT CODES is it throwing, you didn't post them. The ECM is probably already telling you exactly what the problem is.

As for the catalytic converter, unless they used an infrared thermo to measure actual heat coming off it I wouldn't worry about it too much quite yet. Normal operating temp for a cat is around 1000F anyways so it's always going to be scorching hot, that's why there are heat shields on it and the chassis above it.

 

I will get the exact codes that are stored and update you. When Firestone scanned the car yesterday there were no active codes only stored. Heading there now.

 

Having the car towed to a friends shop Firestone just called stated their diagnosis determined the rear cats went bad. They're recommending replacement along with new spark plugs. Quoted me $6100 LOL. I'll post the codes once I get it to my friends shop. I just dont see how the car was driving completely normal and after this oil change the rear cats just instantly clogged up/went bad? Update soon thanks again for the replies.

 

Just make sure to keep track of all documentation in case Firestone did screw with something they shouldn't have.

 

6100 for that? Damn that is a huge rip. Change the plugs yourself (easy) and then do the cats with some aftermarket HFC. I've done the cats probably a half dozen times (to pass Smog, lol), it's not hard once you break the demon bolts loose. A lot of threads about the cats here and on MyG37

 

UPDATE

So it turns out this particular Firestone location tried to sabotage the car and scam me out of almost $6,000. I had the car towed to a friends shop and he discovered that they had intentionally folded the bottom of the intake tube from the filter to the throttle body in causing a huge unmetered air situation but it wasn't visually apparent because it was underneath. After having my friends shop clean the MAF sensors and switch them with no success he found the incorrectly installed/seated air intake. Reseated properly and reinstalled and the car runs just like it did before I went there for the oil change. Currently in the process of having Firestone refund me for the oil change and reimburse me for the tow and diagnostic fee/labor at my friends shop.

 

Damn, sorry to hear you went through all of that. But glad you got it squared away and kept the 6k in your pocket.

 

Not to doubt you but playing devil's advocate, how do you know it was intentional and not just incompetence?

In any case, I don't need to tell you that a good shop can be hard to find. I work in the parts industry and get to know some reputable shops and some scum bags. But usually do all my own work except tires and state inspections.

 

Hanlon's Razor!