Starting Woes, and limp mode... Need Input!

S

SCY7H3

Member
Car
2012 FX35S AWD
Hey guys,

Hope some of you could chime in and help a fellow FXer with some weird issues.


Long story short, almost every morning when starting the FX, it starts but immediately feels like it will stall then idles fine. The cold weather seems to affect it more.

There's also an issue where after a good 15-20 minutes drive, if I park it for 20-30 minutes and try to start it, it will start and immediately die. What I would then do is try to restart it giving a few seconds in between until the sixth time it would actually maintain idle after struggling a bit.

Then I've had a few instances where the car would eventually go into limp mode after a good 15 minute drive where any form of accelerator input is delayed and not very reactive. It almost feels like the computer is preventing the engine from achieving any normal operator performance. Almost like having snow mode on but worse.

I'd right after move off the road, turn off the car and once again I wouldn't be able to start the car until the 6th try and it would still be in limp mode. I'm guessing because of the codes, the car's in a safe mode.

Then there's times a restart would clear the issue and the car would drive normally again.

I've had an opportunity to pop in an ODB2 while it went into limp mode and two codes would pop up. P0101 and P010B. When looking these up, has something to do with both MAF sensors. I took a peek a both sensors and didn't see anything wrong with them.

Honestly I'm not sure what exactly is the issue. I've check the sensors, filters, checked the wires. Reset the ECU, re-did all the Idle Air, etc relearning procedures and it just won't go away.

Any thoughts?
 
Finally had this issue resolved. Ended up being two throttle bodies that were failing but not enough to throw a permanent code.

Replaced under warranty. The car now flies, honestly I've been missing out for god knows how long.

The two codes only show when the car goes into limp mode...if you turn it off and back on, the issue tends to clear itself and the codes won't be retained.

The limp mode comes on when the ECU detects an abnormality with the throttle electronics and basically does a "safe mode".

After the throttle bodies were replaced I have no more issues with my 7-speed transmission. Before the transmission wasn't sure what gear it wanted when I was pushing the accelerator more to overtake a vehicle.

I think the failing throttle bodies were giving the ECU mixed signals thus giving the transmission wrong information and it was acting based on that.

I'm pretty sure they reset everything.

As for throttle body cleaning, they never said anything that they were dirty. My scenario was component failure. The fact that it was two throttle bodies surprises me. But who knows, maybe there's an issue with throttle bodies failing.

Hope this helps anyone that is experiencing the same issue.
 
Good to hear you got it resolved!

Reminds me of my issue where I had a head gasket leak on the coolant side of the number 7 cylinder. Took forever to track it down, like 2 years I'm guessing, and during that time the car would idle poorly sometimes and perform badly. This got worse as the coolant fouled the plug more and more... eventually air pockets developed and the engine overheated.

During all this time they never pulled the number 7 plug to check it until the overheating. Duh.

Had the new motor for almost 2 years now and it's so nice having a rocketship again :) It's also nice having a car with 46,500 miles but an engine with only 4500! Yeah I've been putting little miles on it and it stays garaged. One of the perks of working from home ;D
 
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