2009 4.6L will not rev. above 3000

[browndrill]

I apologize if this has been address previously, but my 2009 4.6L sedan, will not rev above 3000. It has previously shown a right bank too lean error code, and currently shows a right bank catalytic converter efficiency low code. Any ideas where I should start looking?

Thank you in advance,
Matt

 

[Qship]

Most likely your cat is plugged up so exhaust can't get pushed through which is causing WAY too much back pressure and stopping the engine from pumping more air/fuel. Not a good situation to be in (been there twice in other cars). When I had this happen, we removed the upstream O2 sensor so there'd be somewhere for the exhaust to go. Went for a 2 second blast in the parking lot and car had full power. Replaced cat, no issues again until a monster misfire fried that cat too. Different car, but same test method would tell you if it's the cat or not.

 

[LarryK]

just tried mine it goes 5+ easy .. I was scared to go further

 

[Gunkk]

I apologize if this has been address previously, but my 2009 4.6L sedan, will not rev above 3000. It has previously shown a right bank too lean error code, and currently shows a right bank catalytic converter efficiency low code. Any ideas where I should start looking?

Thank you in advance,
Matt

Most likely the car went into limp mode (RPM/power restriction) due to an excessive lean condition (Right bank lean) and also likely excessive knock. Limp mode is intended to prevent lean induced detonation that will wreck the engine.

Lean means too much air and/or not enough fuel. 1st thing would be to check for proper fuel injector function. Then fuel filter, etc. Then manifold/intake air leaks after the MAF.

re: plugged cat
It is possible, but such a thing would more often trigger (and be caused by) a rich condition, not a lean. Less air flow due to high backpressure would mean less air in the cylinder, not more. A burned out cat would be the more likely with a "low efficiency" code simultaneously with a "lean" code.

YMMV of course