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Revving while in park, related to accident?

I have a 2004 Honda accord ex (leather, sunroof, alloy wheels) this Saturday the 26th I was hit by a lady. She hit my rear passenger side fender right behind the wheel. Its minimal damage. At the moment of impact I slammed on the breaks. Hard enough to sprain my foot. So today (30th) I was on my way to take it to repair shop for an estimate on repair when I my car started acting up. I was stopped at the light and I let my foot off the break to inch up behind the car in front of me. Surprisingly the RPM’s revved to high up (3 or 4) and I almost hit the car in front of me but hit the break in time. I thought it was strange but I carried on pulling into the repair shops parking lot. As I’m pulling in its still revving the whole time where I almost hit a parked car. Finally I park the car and I step on the break and set my E break. To my surprise the engine is constantly revving. It goes up to 3 or 4 RPM’s and the drops. This goes on continually and scares me. So I shut off the car since applying the break does not stop the revving. (ps I checked and I was not on the gas) Well the repair shop and my insurance doesn’t think it’s related. Can anyone out there help me or tell me if it’s possibly related?

The only think I can think of is if you hit the brake so hard you damaged the brake booster… This would cause a major vac leak, and may casue the motor to run very fast (as it is sucking more air in, it will burn more fuel)…

This is the only thing I can see making these two related. A simple check is to pull the vac hose to the booster and plug it up… If the car idles normally then you know your booster is bad.

Without knowing why it is revving high there’s no way to say. Find out what is causing the high revs and report. Then folks can comment.

After you hit the BRAKES, you should take a BREAK after working so hard. Could be related but they will have to check out the source of the high RPM. Depending on the cause will determine whether it is related or not. They can make a note on the estimate pending the resolution. I suppose the computer could have been damaged so just have it diagnosed and fixed first.

The repair shop cannot determine whether it’s related until they diagnose its cause. Once they do, if it’s related it should be included in the insurance claim. If it’s not, you may be out a few bucks. But if it’s not, it would have pappened anyway.

The first easy thing to check is the floor mat. Make sure it isn’t on top of the gas pedal. It may have slid forward during the collision when you slammed the brakes.

@gsragtop @cigroller @bing @thesamemountainbike The body shop could not find a cause. I then had it towed to a mechanic and he could not find a cause or even have the problem arise. Suggestions? Is it safe to drive?

Since I was left out, you must not be addressing me, but I still think it’s possible it might just have been the floor mat.

Was it you who disagreed with me? If so, I would like to know how you ruled it out. Are there no floor mats, or is the floor mat secured to the floor of the car?

Just for fun, check your coolant level.

@whitey Sorry to leave you out. I was addressing those who wanted to know the results of taking it to a mechanic. the floor mat does not seem to be the issue. I’m not sure how I could rule it out but this may help; The “tech” at the body shop checked it out. He said it would “high idle” for him but only from a cold start and it wasn’t that bad of a problem. Very belittling in his manner. He said they checked all the vacuum hoses and it was fine. His only other idea would be that the engine had a problem. But he wouldn’t touch the engine because it was a “honda” and was it pristine condition, not even a drop of oil on it. Ideas?

@shadowfax I don’t have possession of the car to check that. But I will and let you know. I’m curious as to what you think that might have to do with high idle?

If there is a floor mat on the driver’s side floor, and it isn’t secured to the floor by the hardware supplied by Honda, I’d feel safe after having the car thoroughly checked.

I suggest you either remove the driver’s floor mat or make sure it is secured to the floor. Also, find an empty parking lot and practice how to stop in an emergency like what would happen if your throttle were to stick in the open position. Practice by picking up some speed, shifting into neutral, and bringing the car to a complete stop before shutting off the engine. After you do this a few times, you will be ready to react if this happens while you are on the road.

Having a throttle stuck in the open position is not as dangerous as it seems if you know how to react. It’s only when people panic that they plow through a crowd of people or into someone’s house because of a stuck throttle.

If this ever happens to you, be prepared to hear the engine scream. It will rev really fast if you shift to neutral while the throttle is stuck open, but don’t worry. Your car has a rev limiter that should prevent catastrophic engine damage, and even if the engine is damaged, I’d rather damage my engine and prevent a collision than collide with something and possibly kill someone.

Once you’re back in possession of that car, if it happens again, pop the hood and look at where the the throttle cable goes. See if it appears as though someone is pressing on the gas pedal. It may not be the gas pedal that’s opening the throttle, although that is possible as whitey suggests:
Since you probably have everything on that car, including cruise control, I wonder whether the cruise control servo wasn’t shifted somehow and the cable is opening your throttle.
That’s on the passenger side of the car, if I remember correctly.

Hondas especially are known for revving the engine when the coolant is low or has air bubbles in it. I have serious doubts as to the possibility that this revving would cause the dangerous situation you describe, but if it’s combined with something else, like loss of brake effectiveness due to other damage, or a faulty throttle position sensor or something, then it might make you roll a bit. Usually the revving is between 750 and 1500 RPM, however, so it’s a shot in the dark, but I think you’re reduced to shots in the dark if your mechanic can’t find the cause.

When are you supposed to go get it, since they can’t find anything wrong with it? If you pick it up and it does it again, pull over, put it in park, and if it’s still revving, check your floormat. If it’s touching the throttle, then pull it away. If not, then floor the throttle briefly and see if that makes the idle come down.

@whitey Thinking back to it, If the floor mat had slid onto the gas pedal wouldn’t me pressing on the break stop the revving? As well as wouldn’t it be a constant supply of gas making it stay at the 4 rpm? Not falling down to 0 and revving back up to 4 and repeating over and over again? Who know’s it may have been the floor mat. My main concern is if there’s a problem… why can’t two mechanics find it?

No pressing the brake does nothing to the revving. It just stops the car.

One of the “mechanics” is a body shop technician. He knows how to bang on metal until it’s approximately the same shape it was before the wreck.

The other mechanic, we know nothing about. It’s not as though all mechanics are good at their job.

@DanniBM, if you have a throttle stuck in the open position, pressing the brake does nothing to slow the engine down. The brakes only slow the car, not the engine. Also, remember floor mats are floppy, so I don’t think you’ve ruled it out until you’ve removed it or secured it.

Honda floor mats come with a hole on the edge closest to the seat and hardware to attach them to the floor. Frequently, Honda owners don’t bother setting up this hardware (I haven’t with my Civic), but in your case, either use the hardware to secure the floor mat or take the floor mat out. This way, if it happens again, you will know it wasn’t the floor mat.