Nick Dude
New Member
Hello, recently acquired a 99 Honda Civic LX. 192000 miles, had been sitting a couple of years. Started it up an idle began jumping up and down between 1k-2k *vroom vroom vroom* and was told, TPS sensor.
Changed TPS sensor and solved jumping idle, but now idled too high. Didn't bother calibrating TPS; had to turn it all the way counterclockwise just to keep the idle about 2k. Idle would increase as I turned TPS clockwise, upwards of 4k.
A friend then checked computer and got codes:
P0108 - MAP sensor circuit high input
P0122 - TPS circuit low input
So I changed the MAP sensor as well.
Now idles about 1k at startup, but will rise to 2k/2.5k after running a while. Also the automatic shifting doesn't shift gears until around 3.5k (though some people said that is normal for a Honda?). The shifting is smooth, but seems very high rpms for a shift. Shifting down is jerky. Seems wrong to me.
Checked the computer again and got same codes as above, plus a code referring to the IAC. Can't recall the exact code as I forgot to write it down. But I'm surprised I'm still getting the codes for the TPS and MAP inputs, as if I haven't even replaced the parts.
I'm going to pick up an IAC valve and see what it does, but wanted to see if anyone had any input at this point, perhaps having had something similar happen with their vehicle. The gas mileage is now about 20mpg which seems really low (though the air filter is dirty and needs replaced, so could be part of the gas mileage problem).
Any advice or input is appreciated. It is a good little car, and I got the Hanes manual and plan on taking good care for as long as possible, but need to find out how to fix this problem first. I have no money for professional help so that is out, and why I need to learn this stuff myself.
Thanks for any help.
Changed TPS sensor and solved jumping idle, but now idled too high. Didn't bother calibrating TPS; had to turn it all the way counterclockwise just to keep the idle about 2k. Idle would increase as I turned TPS clockwise, upwards of 4k.
A friend then checked computer and got codes:
P0108 - MAP sensor circuit high input
P0122 - TPS circuit low input
So I changed the MAP sensor as well.
Now idles about 1k at startup, but will rise to 2k/2.5k after running a while. Also the automatic shifting doesn't shift gears until around 3.5k (though some people said that is normal for a Honda?). The shifting is smooth, but seems very high rpms for a shift. Shifting down is jerky. Seems wrong to me.
Checked the computer again and got same codes as above, plus a code referring to the IAC. Can't recall the exact code as I forgot to write it down. But I'm surprised I'm still getting the codes for the TPS and MAP inputs, as if I haven't even replaced the parts.
I'm going to pick up an IAC valve and see what it does, but wanted to see if anyone had any input at this point, perhaps having had something similar happen with their vehicle. The gas mileage is now about 20mpg which seems really low (though the air filter is dirty and needs replaced, so could be part of the gas mileage problem).
Any advice or input is appreciated. It is a good little car, and I got the Hanes manual and plan on taking good care for as long as possible, but need to find out how to fix this problem first. I have no money for professional help so that is out, and why I need to learn this stuff myself.
Thanks for any help.