Engine Performance problem
1994 Mazda MX3 4 cyl Two Wheel Drive Manual 179000 miles
I recently killed my car battery by leaving the headlights on. It was idling sorta rough before this but there wasn't any problems until after.
I went to have my friend jump start it and he attached the jumper cables backwards (possitive to neg, neg to poss) and blew the main fuse.
So I took the battery out and had it charged and replaced the fuse and then it started right up and drove fine for about 10 minutes and then it started to idle really rough when we were stopped. Then we noticed that it that the rpms while idling were going up and down (from less than 500 rpm to a little over 1000) Then it started idling lower and lower, until it was stalling everytime I stopped.
It drives fine, it just dies while idling.
I read online that if you start it and give it some gas when it starts to die, it will relearn where to idle so the next day I started it up and let it idle for about 20 mins. At first it was fine, although the rpms were still going up and down a small amount but as the car ran it started to vary more and more. So I gave it some gas when it got low and it seemed to have actually stabalized for a while.
Then I popped the emergency break and the rpms dropped down a lot lower. So I gave it some gas, and it didn't stabalize this time. Then I put the emergency brake back on and the rpms went back up, but they were still varying a lot.
I have no idea what's wrong with it. I did think it was related to the car being jumped backwards, but it did start to idle really rough after being driven for a while before. I have no idea if the emergency brake actually has anything to do with it, but it did seem to make a difference.