Hard start stumble at idle

I have a 97 with a 2.2 automatic with air. It is hard to start especially the colder it gets. When setting at a red light at idle, it stumbles a lot. It has no rythm to it or time between is variable. It almost seems to get worse the longer it is run.

One really cold morning it wouldn't start at all. When it warmed up a bit I got it started and dumped in some Lucas fuel treatment, it ran a lot better for about 3/4 of the day, now it is getting bad again.

I plugged in my actron scanner, it has no codes and the running tests were all OK.

Does this car have a fuel filter or is it built into the pump like many are? I would figure filter if it has one, then injector, then pump, then I guess I would check plugs and start down that road of ignition. Can't figure on a sensor of some type because of no codes and run tests being OK?

Any other ideas or am I on the right track?

thanks mark

Sorry to reply to my own thread, but I did a regular tune up, plugs, wires, oil change, fuel filter, air filter, and PCV valve. One of those seems to have fixed it.

Would have probably been the fuel filter that you changed. If it gets clogged up, gas isn't going to the engine like it should, and naturally making the car stumble.

I had a terrible time getting that filter off. It had a built in plastic insert to push in to disengage the tabs. It was so worn it wouldn't work, tried WD and blowing out with air, in the end I had to break the plastic out, cut the tail off the filter and use the gas line removal tool to disengage the tabs. The tool wouldn't fit between the body of the filter and the connector. The trouble is the new filter didn't come with the new built in removal tool, so I will have to do the same when this filter needs replacing. Is there an easier way?

At least in this case the problem had an easy fix, ie the tune up which needed done instead of a higher dollar harder to do fix.

replace your oxygen sensors as well

my guess because the lucas treatment worked(at least fo a little while) that it would be faulty ignition. and does the car overheat at all??? an easy way to tell its injectors is have the car running pop the hood then poor a tiny bit of water over each boot if it stalls or skips it that injector.but in cases like this (no codes) its a guessing game sometimes.