glanga88

Hey all,

Gf has a 2012 RDX that feels like there is a misfire. It's most noticeable when you lightly accelerate in the top gear, 5th I guess? The dealership said there is nothing wrong after taking it for a test drive and being that there are no CELs. They made a note of the complaint in case the car decides to shit its cats out the exhaust later.

I've had 4s, turbo 4s, 6s, and 8s and each has had a misfire so I have an idea what it feels like. Its slight, and easily attributable to the bumpy ride but its definitely there. The dealer said this is normal for a turbo car and attributing it to turbo lag.

Is this a known problem? Has anyone else experienced this?

dcmodels

at what speed (mph)? and does the turbo spool up? is the misfire there whether or not the turbo spools? and you are certain that there is no downshift? what RPM when accelerating? mileage on engine? info provided is too sparse for any idea.

Trying to determine if the *problem* occurs most often under heavy load (low RPM = low engine torque esp if turbo spools up)

You might try duplicating condition when using the SS paddle shifters, so that you are certain there is no downshift, and in which gear the trans is running.

glanga88

This happens before the turbo spools running strictly engine just about any gear. It might be occurring after the turbo spools but I guess the AFRs change once that happens or the power is just so prevalent I don't notice it. There is no downshift. Like I said this happens just about any gear as you are just cruising and give light acceleration before the turbo spools. It's that telltale shuddering caused by a misfire to me. Engine has 20k miles. She said the dealer flashed the ecu today so ill give it a shot tomorrow with the paddles, see if anything changed.

Any experience with those live obd2 scanners? I was looking for an excuse to get one and if I can real time monitor fuel, map pressure, timing etc then id prob get better info.

BigHatch

didn't someone say on here once their pre-gapped plugs were not gapped correctly causing some issues?

glanga88

That is a possibility and I do have a gap tool so I can check that. Did they mean the factory plugs or they bought another set that werent gapped correcntly?

These cars dont have any known problems with ignition coils going or o2 sensors failing? Nobody experiences this sensation at all?

dcmodels

Really? I have had several cars in 50 years of driving, but a misfire seems non-typical, even rare, to me, unless the car has not been well maintained, simply meaning plug/ coil replacements at required intervals.

I would seriously doubt that an RDX with 20K miles has a plug problem, or a coil problem, unless something has been damaged. And I don't think you really want to try checking the plug gap. Its just not practical with this car.

Unfortunately, there are an almost infinite number of other possiblities, for the symptoms that you have described, *simulating* a misfire, from bad gas to a transmission problem.

Either some serious DIY analysis is required, or else put the engine on an electronic scope (machine).

I would first make certain there is a full tank of Premium with a 20oz bottle of Techron PLUS, warm the engine completely (30 minutes), and then run through the gears at full throttle a couple of times from 20mph up to 80-85mph (paddles not required, just let it shift itself). Then recheck for your symptom.

It could be the EGR system, a loose hose on the turbo system, vacuum hose leak, carbon buildup from 20K miles on non-top tier gas, never driving the car other than slow-and-city, etc.

I doubt we can really help by internet diagnosis, w/o some very definite symptom description. Good luck - and interested if you should decide on a definite diagnosis.

dcmodels

Consistently running the fuel tank to less than 1/4 tank, can damage the CATs, according to the OM (owner manual), as well as overheat and damage the fuel pump (its cooled by the gas).

dcmodels

Why? is the reason relevant to the symptom you have reported?

dcmodels

A consistent misfire on any modern car will throw a DTC (code) - you did not say but you must check for any codes, and then have a look at ths thread:

https://acurazine.com/forums/showthread.php?t=889703

glanga88

I'm not really looking for a diagnosis. I was more or less just asking if these cars had any known problems related to this being that forum dedicated to a particular car is a pretty good resource for recurring issues on certain models.

The gas is always premium. And from my experience a misfire does not always cause a CEL light. The misfires I've experienced have come from a faulty o2 sensor and a recall in which oil makes it way into the ignition coil well, nothing to do with improper maintenance.

The cats can also be damaged when unspent fuel caused by a misfire gathers in there and eventually eats away at them.

I dont know what the reflash was. She took the car to the dealership, not me. I havent had time to get into her car and test any of these theories or fixes out.

dcmodels

I tried to duplicate the conditions reported by the OP, and observe the results.

30 Aug 2013
temp 95+ degrees
vehicle at normal temp (driven until warm)
2009 RDX with 40K miles

Turbo spool-up means the turbo-gauge-needle moves off the bottom rest-position. The indicator needle may not move much, but any movement means that the turbo is spinning enough to create some boost. The gauge does not have to move to 1/2 of display range, in order to indicate some boost.

At 50mph steady in 5th gear, apply just enough throttle to increase speed enough to observe at the mph gauge (or feel), and the turbo will *always* spool-up a little. This is normal, as the engine control system is designed to do this to improve gas mileage, rather than perform a trans down-shift. I could not observe any significant delay (lag) between throttle increase, and turbo spool-up.

Any increase in throttle over minimum, will also show the turbo boost-gauge will increase by a commensurate amount.

RESULTS:
For minimal throttle increase, under the above conditions, I could feel nothing other than a smooth (minimal) linear increase in speed.

For a slightly greater throttle increase, I could feel a slight *sudden* but almost imperceptible, increase in speed as the turbo boost gauge needle (indicator) would move upward a bit quicker rather than a smooth linear increase. It’s the turbo kicking in with more boost. Not a jerk, but a slightly sudden vehicle speed increase – not like an engine *miss-fire* which causes the opposite sensation – a slight slowing (or hesitation) and possible jerking.

CONCLUSION:
If the OP does not observe turbo spool-up, by observing the turbo-gauge, even a minimal amount, with *any* throttle increase, then there is something wrong. Maybe there is a vacuum leak, or a pressure leak in the turbo/ intake air system.

If the OP cannot observe or *feel* the turbo contribute to the vehicle speed increase, for a greater throttle increase, then again, there is something wrong. Perhaps the turbo is not spinning (spooling) up correctly. Why? Well, there are almost too many reasons to list: vacuum system leak, coked turbo bearings, leak in the air intake system, electrical sensor failure, etc.

Don’t know if the preceding is helpful, but its what I observe with my 2009 RDX.

dcmodels

They have a small number of known problems, but I have not seen anything reported similar to your specific question for an RDX - many reports for TLs but its usually the sensor on the throttle (DBW drive by wire) system, but not always - see the link I listed in post #9 above, and search. If not a diagnosis question, then what? I was assuming by *diagnosis* simply some response indicating a similar problem (and cause), and I don't know of any for an RDX.

n7plus1

Bumping this thread...my wife's '12 is experiencing this issue under the same light to heavy load in top gears on the highway. It certainly is misfires...

34k miles.

OP, hopefully you sub'd this thread and can give some feedback or update?

Tomtwtwtw

My Honda Fit experienced the exact same thing - misfires under high load / low rpm on the highway. I found a crack in one of the spark plug coils - replaced all 4 and misfires were gone. I recommend at least looking at yours...if you're not familiar with accessing them, follow the instructions / pics in this spark plug change DIY thread.