The car was working properly when I drove home from work yesterday, but it got cold and a little snowy overnight.

This morning while driving to work, I noticed that the car wasn't slowing down when I removed my foot from the accelerator. It would keep going at about 25 mph. When I moved it into neutral, the car reved between about 1200 and 1700 rpm. I made it to work and let it sit for a few hours, and I'm seeing the same thing.

I'm not super savvy with repairs, but any ideas are helpful. If nothing else, I'd like to have an idea of what may be going on when I take it to my repair guy.

Thanks in advance.

 

Verify the carpet or floor mat is not getting bundled up on the pedal.
Verify your shoes/boots are not catching the throttle when depressing the brake.
Open the hood and verify the throttle cable is allowing the throttle to fully close, exercise the thorottle by hand and make sure it goes back to the throttle stop.
Look for any debris that may have gotten kicked up by the snow and not allowing the throttle to fully close.

 

It might also be that your throttle needs to be cleaned. Watch Scotty Kilmer's YouTube video "How to fix a car that idles poorly" The throttle plate can get carboned up with soot and won't smoothly open and close - some times it gets stuck. I have an 00 Accord and have done it - you just remove the air intake from the throttle body and spray the throttle plate with Throttle Body Cleaner that you can get at any auto parts store, and wipe it off and let it dry - it's all in the video.

 

This issue, if not caused by a sticking throttle, ice or snow, can be caused by a vacuum leak. Could be a disconnected or cracked vacuum hose. Just something else to look at while you have the hood popped open.

 

Didn't seem to be anything blocking the accelerator in the car. Took it into the shop yesterday evening.

Repair guy just called - said that the IACV was shot. He's replacing it and said that these often die due to bad/old coolant - recommends a radiator flush. Is that legitimate? I know the radiator hasn't been flushed in a long time. Losing confidence in the shop, and I'm wondering if they are taking me for a ride.

 

I have personally never had an issue with coolant rotting out an IAC valve. I would only imagine that if coolant had got into the IAC you would have seen white smoke out of your exhaust and coolant in your intake manifold.

Was the valve contaminated with coolant?

Have you had to top up your coolant lately?

Yes IAC valves have been known to go bad. but I have yet to see one fail due to bad coolant.

Just an FYI, these valves do not require those coolant lines to operate. they are only there to help keep the valve from frosting up. I bypassed my IAC coolant lines years ago. Ran it from 30*C to -30*C without any IAC operation issues! IAC is operated by the ECU based on signals from other sensors in the PGM-FI system.

 

Thanks for the info.

Sounds like the coolant flush wasn't exactly required at this juncture, but I know it hasn't been done since turning over the 120,000 mile mark either. So it was probably needed, but it does sound like I was being a bit mis-lead as well. May be time to hunt for a new mechanic.

I appreciate all of the help and insight here. I hope you all have a good weekend!

 

So the whole thing of using a F22B1 IAC on a F23A1 manifold, with an adapter, and having the coolant lines interfere with the throttle body is really a non-issue? And all I have to do is block them off and I am good to go? Where I live it rarely gets below freezing and the car is garaged.

 

Yes sir! I ran my 96 F22B2 5pd Accord for 3 winters with no coolant lines to the throttle body (FITV) or the IAC.

I eventually ran a block off plate on the FIT valve. Before I had made the block off plate I ran a piece of 3/32" gasket material between the FITV and throttle body.

Here is a picture of A FITV delete plate that I quickly put together for a D15 throttle body.



Only thing that I noticed different was that the cold idle RPM in -20 never went up over 1200-1300 RPM. So, the ECU would still use the IAC to allow more air in on cold mornings based on coolant temp sensor input. Where as with the FITV operational, it would go even higher. But that should be obvious as the FITV is there to help warm up the engine in cold climates.