Spudders at idle Runs fine driving

my 1999 Plymouth SOHC spudders at idle but is fine driving. I bought it off someone who bought a truck and put it off to the side for a few months. I was thinking maybe stale gas so im going to drain and replace it and clean the strainer on the fuel pump.

Coolant level was down about half when i got it and i topped it off but last time i checked it, it was down a little not sure if it was just air working out of the system but ill have to keep an eye on that. not sure if it could be connected.

And my temp guage only goes about an 1/8 inch over the bottom normal line even on warmer days (50 degrees F here) but it puts of plenty of heat is that normal?

ok so i changed the gas out and there is no change. so i started the car and while it was running i unplugged injectors one at a time and when i unplugged #2 (second one from timing belt) there was little to no change. i pulled the fuel rail off and cranked while watching them and they all sprayed equal non seemed stronger or weaker. so i checked the plugs still nothing wrong so i swapped out #1 injector and spark plug for #2's and there is still no difference. I have some codes but i think some are from me unplugging injectors.

12
27
27(comes up twice)
42
55

possible timing belt skipped a tooth and is causing it to fire at the wrong time?

checked the old fashion way for bent/burnt/sticking valves by holding a dollar to the tail pipe when the engine is running cold not warm and it tried to suck the dollar in every so im sure its a valve problem.

which could it be? (bent/burnt/sticking)

the idle smooths out a lot when warmed up but still a bit shaky but at higher rpms 1000 + it runs without a miss.

Most likely sticking valve?

*Code 12 - battery disconnected within the last 50 key-on cycles (common code)

*Code 27 - injector circuit (probably from disconnecting the injectors)

*Code 42 - ASD/fuel pump relay may be bad and/or faulty (try swapping it with the horn relay to check functionality)

*Code 55 - end of codes

alright ill check that tomorrow. but would could be causing the (what i believe to be) valve problem?

runs rough at cold start but once it warms up it runs a little smoother but still shaky idle.

If i pull the injector on #2 (second from timing belt) there is almost no change in how the engine runs.

so that means either a valve isnt seating right or is sticking. correct since its getting gas and spark to that cylinder?

but i doubt the timing could be that far off and the engine still run.

You could try running some seafoam through the engine to clean out some of the gunky buildup in the engine.

don't know if this helps any but it runs almost as if it is cammed. kinda has that idle chugging at cold start and when it warms up runs and sounds like its cammed. ill check on that relay though right now.

Would running half quart of tranny fluid in the oil help cause im a little weird about adding seafoam ive heard good and bad things about it.

I'd be just as leary about the tranny fluid as well. But you could give it a try.

this chug a chug at idle sounds just like what mine did. i just disconnected the egr and its been ok since

hmm its worth a try. its too dark out to try tonight but tomorrow ill try to disconnect it.

wouldnt it trip the light though?

or at least store a code?

alright when i disconnect the vaccum hose the car idles perfect. when i remove the hose from the bottom a bit of what i think is water sprays out. so for now ill drive it with the egr vaccum line disconnected till i have more time and money to look into it.