Car drives without foot on gas

SKYY797

MEMBER
2006 HONDA CIVIC
1.8L
4 CYL
FWD
AUTOMATIC
115,000 MILES

I recently cleaned the throttle body of my car because it was idling a little rough. I am 100% positive I put everything back correctly and there are no error codes. When I cold start the car and I take it from park to drive, it idles like a dream (I fixed the rough idle issue). But when I take my foot off the brake it rolls normally, then a second or two later it will start accelerating out of nowhere (it is slow at least). I have tested to see how long it will do this for, and I believe it will keep going.I have gotten to upwards of 30 mph without my foot on the gas. This is very unsafe when driving to and from work for me (especially when it does it in reverse). What could possibly be the issue?

Thanks,
Kevin

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

When you cleaned the TB, tell me how you did it.

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Thursday, March 5th, 2015 AT 6:36 PM

SKYY797

MEMBER
2 POSTS

My dad had some special cleaner that he had used for his Tacoma a while back. We used that plus a paper towel, there was some liquid type gunk that had built up around the flap that we cleaned and then wiped it down with a dry paper towel to remove everything. One thing I was talking with my dad about is we didn't make sure that we tightened the clamp on the hose that attaches on the throttle body and goes from the throttle body to the air box. Could that possibly cause the issue if the clamp wasn't on correctly?

Thank you very much for your time btw,
Kevin

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Thursday, March 5th, 2015 AT 6:57 PM

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

Kevin:

Yes, that can cause an issue. The mass air flow sensor (MAF) iss before the Throttle Body. If the engine is sucking air because the intake air tube isn't connected, the MAF is being bypassed or sending incorrect information to the PCM. Thus, the computer is trying to compensate and causing the idle to increase. Check that first. If that doesn't fix the problem, make sure nothing was left disconnected and there are no vacuum leaks to the engine. It's easy to bump a hose and not even realize it's disconnected.

Let me know what you find.

Joe

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Thursday, March 5th, 2015 AT 7:17 PM