Travis Lester

Hey guys,

I've got a 1999 Civic LX with a 4-speed automatic trans that stalls whenever I push the gas pedal. I just bought the car a few days ago for a couple hundred.
The car starts up decently, and sometimes sits at about 1300 rpms, and when that is the case, I'm able to push the pedal fine and it revs up nicely. However, when the rpms go back down, they sit at about 900 rpms and that's when it stalls when I push the gas pedal. I've got a video of it I can upload to Youtube if that would help the troubleshooting.
I've tried replacing the spark plugs and one of the O2 sensors(Bank 1 Sensor 1, and there was a code for it, P0135 or something. No other codes than that one.) I want to see if more codes would come up, but I can't actually drive the car for the computer to collect data. I also noticed that the exhaust manifold has a crack, so it's leaking, but I'm not sure if that's the problem.
The car had apparently been sitting for a while when I bought it, so I drained the gasoline and put some more in with a can of Seafoam.
Any help at all would be greatly appreciated, thanks.

Travis Lester

Still haven't figured this out yet. I took off the throttle body and cleaned it. I also replaced the MAP sensor on it just in case. Maybe it's the timing? I don't rightly know, so I'm still very much open to suggestions

sumdewd

Honestly you're still at square one with this thing. What spark plugs did you replace with? Civics tend to prefer the basic NGK plugs that are recommended on the label under the hood. Did the oxygen sensor code come back?

And have you inspected the condition of the distributor cap and rotor? This is another cheap and easy to inspect fix. You should also double check the condition of your vacuum lines. Since this is a car you just purchased, what did the prior owner say about it? You may want to also inspect ignition timing and mechanical timing if they have not done a timing belt recently, or even more so if they HAVE done a belt and jacked it up (tooth off). You just need to go down the list and start narrowing things down.

Idle air control valve would be another good free thing to clean.

The cracked manifold is extremely common for this generation, and this model has the catalytic converter built in to the manifold. Two birds with one stone if your catalytic converter is clogged (melted) and choking it out. Amazon sells a Dorman replacement for about $180. Or you can take the time to upgrade. At the very least inspect the converter after you've checked the easier things. I've had similar issues on another Civic with a clogged converter.

Travis Lester

Awesome, thanks for the reply.

I appreciate the to do list, because I wasn't sure where to go with this. I'm not too great with cars, and I exhausted all the options that were on the top of my head lol.
Anyways, I don't remember what plugs I replaced them with. I believe they were the platinum version of the generic brand at the store I was at. The code for the oxygen sensor didn't come back after I replaced the sensor and reset the code, so there are no more codes from the car. In regards to the exhaust and all that, there is a good little bit of smoke rising from that area, so I'm not sure if that points to a clogged catalytic converter or not. I'll have to look soon. And the dude I bought the car from didn't even drive it, he got it from family to sell.
I actually have a mechanic friend that has rebuild the same engine that my car has, so I'm gonna get his 2 cents on it here in the next few days.

Once again, thanks for the reply and the suggestions, I'll start gradually working down that list.

Here's a link to that video I mentioned if interested:

eat5

NGK for sure on all Japanese designed cars, Bad Cat can swamp it like banana in tail pipe....

Travis Lester

Ok, I ordered some of the Iridium plugs from them as well as a new set of wires by NGK. I'm not expecting it to solve the problem obviously, but couldn't hurt.

sumdewd

Dude that thing ran pretty smooth in the video. Does it stay running if you keep on the gas? You might have other issues at hand if so.

Travis Lester

Oh yeah, I figured it out. Meant to post here when I did but it skipped my mind. Anyways, the problem was that the previous people had the spark plug wires plugged into the distributor wrong. like, 3 in the 2 slot I think it was. I noticed while I was changing the wires.
That's probably why I got the car so cheap, they thought that something bad was the problem, when in reality they did it themselves. But, that just goes to show that you should always double check the basic stuff that you assume is already correct I suppose.
The car runs like a champ now, it just sounds like a damned Nascar when the RPMs are high while driving due to the large crack in the exhaust manifold, but I'll replace it. Thanks for checking up though, I appreciate it.

0c00l

Check - Idle Air Control Valve, and possible vacuum leak.

sumdewd

Dude that's awesome. Feel free to post back if you need help with anything else on the car. The cracked manifold is super annoying on this generation

Travis Lester

Fixed it now, thanks though. Although, I don't know what the hell kind of luck it is, but today my trusty Acura started having issues of accelerating on it's own with the throttle completely closed. RPMs go up to about 3000, then dies back down and then goes back up, etc. Probably IACV I'd guess.

sumdewd

I honestly would explore the possibility of a vacuum leak on your Acura. Up and down idle is a tell-tale sign of this.

Travis Lester

Cool, I'll have a look at that. I do hear a high pitched sucking sort of noise so I'll break out the carburetor cleaner. I don't know why these things can't happen on my days off lol

Travis Lester

Fixed the problem with my Acura, it was indeed the Idle Air Control Valve. All gummed up and stuck. With both cars running, I'm in good shape.