weak spark

[ffej999]

I have never done this before so please excuse any mistakes.
I have a 96 corolla 1.6 automatic. It was running fine one day then would not start the next day. It is getting fuel at the fuel rail but don't have tools to check fuel pressure. It seemed to have a weak spark so I changed the cap and rotor, checked continuity and resistance of the coil, pickup coil, crank position sensor. I could not find the specs for the spark plug wires so I bought plugs and wires just to rule out the simple things. Low and behold it started. I used it for 2 days then it started to run poorly all of a sudden (missing and stumbling) then quit. It would start and run but very poorly and with no power. It felt like it was running out of fuel.I had it towed home.
But it also has a very weak spark. I have a simple visual spark tester and my mother has an identical car so I checked her spark and it would produce a strong spark close to an inch long. Mine will not. I don't know what the igniter does or if it can be checked besides seeing if it getting power.
thanks

[ffej999]

I am replying to my own thread. I replaced the coil even though it tested good. The spark is now at full strength. could it be that if the spark gets weak enough that the ECM will cut off the fuel making it act as though it is not getting enough fuel?

[Brian R.]

Bad spark will cause it to act this way.

[jdmccright]

First off, welcome to AF!

A dying coil, even if it tests within the specs, will emit a weak spark before total death.

Hope you replaced with another OEM coil. The parts store brands are not worth the lower cost because they do not last nearly as long. If you went aftermarket, go buy a Toyota one and keep it in the car or handy...you'll need it in about 23k miles...trust me.

Good luck!