Old topic/ Need verification

Mr. Detail · Post by **Mr. Detail** » 01 Oct 2018, 11:04

OK, gentlemen. I think I had asked this question awhile back but I need to verify if anyone can that I am doing the right thing.
When coming to a slow stop at a red light and with the brake applied, the car rev's waaay up to over 4,000 rpm's until I either put it into neutral or take my foot off the brake.
I put a higher grade of octane in above the normal regular 87.
I believe someone told me previously to open up the electronic throttle body (ETM) and wipe the interior with some solution I cannot now remember. I am getting old.

Does this process sound like something that may fix this weird issue?

Post by **RickHaleParker** » 07 Oct 2018, 07:15

Could be the wires to the accelerator pedal are shorting when you step on the brake.
Disconnect the brake booster vacuum line and plug the line. Get in and push down on the brake see if that stops the engine reving.

Mr. Detail · Post by **Mr. Detail** » 07 Oct 2018, 08:15

RHP, when you stated "disconnect the brake booster vacuum line" did you mean the electrcial plug if there is one or the actual rubber hose line itself?
By the way this issue is sporatic. It comes and goes day to day.
Thank you for your response.

Post by **RickHaleParker** » 08 Oct 2018, 01:14

The rubber hose.

Look for brake fluid inside the rubber hose or inside the brake booster. Brake fluid is a flammable, if some is leaking into the intake it could act as a fuel.

As the engine is idling, loosen the plug you inserted and let some air in see if it revs up. If your fuel mixture is rich and the brake booster is leaking air into the intake, that could account for the rev up.

Sporatic does point more so to a electrical problem, inspect the wiring to the accelerator pedal.

Post by **oragex** » 08 Oct 2018, 05:11

I too feel it may be connected to the brake system, such as a booster/master leak or a vacuum issue. Just don't rush into replacing these until really sure. Try once to slow down with the parking brakes - on an empty road, see if it does the same.

But also make sure it's not the floor mat or the tip of your shoes grabbing the gas pedal by inadvertence. You never know

Cleaning the throttle body is very easy on a n/a. Just undo the large air hose at the right of the tb, then clean the flap in and out (keep it open by hand) and the body as well near the flap hinges. I don't think you need more than a piece of wet fabric/sponge.

Mr. Detail · Post by **Mr. Detail** » 08 Oct 2018, 06:16

Thank you everyone!

Post by **abscate** » 08 Oct 2018, 06:50

Use a throttle body cleaner spray and soft paper towels.

Keep the electronic part of the throttle body up so your solvent doesn't work into the electronics -a little is ok, a deluge maybe not - and an expensive lesson to learn if its too much.