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My gas pedal got stuck and now my car is making noise, getting poor MPG

Maintenance/Repairs
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#1

Hi all.

Back story:
I floored it on I-90 to get out of the way of some snappy lexus speeding up behind me with a driver on the phone. (I was next to a truck so couldn’t change lanes.) My gas pedal got stuck to the floor, so while I figured out what to do, I rode the brakes as hard as I could. My car is automatic but has 3rd, 2nd, and 1st gears, so I downshifted to 3rd while on the phone with the state police. After pumping the gas a few times, the pedal came unstuck and I had a relatively normal 2.5 hour drive to my home. This was about a month ago.

Problems:
Noise: Since then, my car has been making a noise that (thanks to mycarmakesnoise.com) sounds something like a slipping transmission or a hole in the exhaust system; the noise is noticeable at just over 2000 rpm (about 2150 to my eye) and is more pronounced with acceleration.

Ride: It feels a little jerky around the point you’d want to change gears on a manual transmission.

MPG: The gas mileage has also changed: I’ve put about 700 miles on the car since “the incident” and she went from getting over 380 miles per tank to under 300 miles per tank.

Questions: (in increasing order of importance)

  1. Could it be as simple as burnt transmission fluid?
  2. How can I differentiate between an exhaust system problem and a transmission problem?
  3. What’s wrong with my poor baby?!
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#2

First, did you have someone investigate why this problem happened? If not, this car is a safety hazard that shouldn’t be on the road with others.

Second, if this happens again, you need to shift into neutral, not one of the other forward gears.

#3

Welcome to the forum. If I may, I’d like to suggest that you change your user name to Courtney (anything but your last name). You never know what kind of weirdos are trolling a site.
I am sure you realize this now, but never let a moron dictate how you drive. My rear bumper has been cussed out by many idiot drivers, but I refuse to endanger myself getting out of their way.
Have you ever checked your tranny fluid? (Owners manual has instructions). On cars I am familiar with, the oil dipstick is usually yellow, and the tranny is usually red. You can pull it out and wipe it on a paper towel. Cherry red is the desired color, as it approaches dark brown, it is getting worrisome.
Check with friends etc. to see who they use as a mechanic, and make an appt. to have it checked over.

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#4

Your transmission has to be checked with the engine running in park or neutral with the car driven about 7 miles to warm the fluid. It should be clear red.

Any muffler shop should be able to show you a leak, if they can’t show it to you, plead poverty and drive away.

#5

@courtney.gibbons This is very good advice.
Second, do you have a friend or relative who would know what an exhaust leak sounds like or can look under your vehicle for damage?

#6

Glad you are OK. That must have been very scary! I will leave it to the more qualified to answer your troubleshooting question, but my first concern would be “Gas pedal stuck…”

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#7

With the car off, open the driver’s door and kneel down by the footwell so you can see what’s going on. Push the gas pedal to the floor and see if it can get hooked up on the floor mat or is just a worn out bushing that is causing it to get stuck. The floor mat is easily fixed, a bushing will need professional intervention.

The other advice on checking fluids is good for that aspect.

If it’s cold where you live, you can often check for exhaust leaks first thing in the morning when everything is stone cold. The same fog like exhaust may be puffing out from further up the exhaust system if you look under the car with it idling.

This is what amazed me from your original post. While in the midst of an unintended acceleration episode, you managed to dial the state police on your phone and have a conversation while trying to wrest control back??? Pretty impressive!

#8

Thanks! I appreciate the advice. Regarding the multitasking: I am extremely calm under pressure. :slight_smile:

#9

Looks like I can’t change my username. I’m stuck with my naivite.

#10

Thanks for the advice. I made the split-second decision that I couldn’t shift into neutral without endangering the drivers behind me at the time.

#11

@cdaquila can you help the OP change her username to take her last name off?

#12

The system is showing a new username of virtualcourtney – somebody seems to have changed it before I got here? Anyway, Courtney, if you log out and log back in to cartalk.com, your username change should show up.

#13

Just tried. Seems to be stuck. Elsewhere on the site I see “virtualcourtney”

#14

Let me clarify a few points: I got the car checked immediately after the initial incident. The gas pedal got stuck because the linkage was rusty (that was the first time I’d literally pushed the pedal to the floor). I knew it wasn’t a simple mechanical problem because I could move the pedal with my foot but it was essentially limp. (Pumping the pedal got the linkage moving again)
I also had the brakes checked out and serviced. The problems that I wrote about appeared later.

I’m concerned that the check engine light hasn’t gone on with such a drastic change in fuel efficiency. Shouldn’t the O2 sensor register that I’m getting around 25% fewer miles per tank?

#15

Have you noticed at what speed the transmission shifts into its highest gear, and what the RPMs are then, and how does that compare to before the incident?

#16

There can still be diagnostic codes stored in the engine or transmission computer memory, even if the check engine light isn’t turned on. That’s one place a shop can check to get the ball rolling, the OBD II diagnostic system. Reduced mpg might not show up as an O2 sensor problem. The most common reason for reduced mpg is the driver isn’t measuring it correctly and consistently, and the next most common is something wrong with the engine cooling system temperature. Less common, the number of miles driven registered on the odometer is not accurate. Since the odometer input comes from the transmission usually, that should be a suspect here.

Do you notice the engine coolant temperature gauge is acting unusual at all? Not like it used to before all this? It should be in the mid-range on the dial once the engine warms up. And it should only take a few minutes to warm up to operating temperature after a cold start, 10-15 minutes max. Is all that ok? You can test the odometer accuracy by finding a road that has mile markers. Many freeways have small posts positioned at exactly one mile intervals.

If your transmission jerks when changing gears (more than it used to), that might mean you are due for a proper transmission service. On most vehicles that means dropping the pan, cleaning it thoroughly, checking for signs of metal debris in the bottom of the pan or in the fluid, changing the transmission filter, then a refill. If you are due for that anyway,now would be a good time to schedule it. No sense spending diagnostic money searching for a solution until all the routine maintenance is up to date.

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#17

I would also consider checking the brakes again. Drive for a little while 20 minutes or so and when you stop, in a safe place, carefully check the temperature of each wheel to see if one is significantly hotter than any other. The fronts should be similar in temperature anf the rears should be similar to each other. If one is hotter, it is dragging may have a sticking caliper or an internally failed brake hose.

Based on your throttle problem - rust - because you never go full throttle, the brakes may be in a similar situation and your hard braking to overcome the engine may have caused a problem your mechanic didn’t detect.

#18

Thanks everyone! Based on your advice, I’m bringing my car in for a
transmission service (the transmission fluid looks burnt) and a brake
service (no noticeable temperature differences in the tires, but I would
rather have my brakes in perfect condition than chance it).

1 Like