Here'* an update. I've added the half can of Seafoam to gas tank in addition to changing plugs and wires and one coil pack. Car seems to be running better but I'm still occasionally getting a slight stumble at ignition and the jump in rpms to around 2000 before it settles down. Does not happen all the time but it still is happening. Also check engine flashed 3 times today and then went out when car was started, this is the only time that'* happened since end of last week.

The Seafoam will take a few days to be effective.

Have the car scanned for codes.

Update from this morning. Car started and idle was very slugglish and stumbling, thought it was going to stall. Checked engine flashed twice and then stayed on, code given is
P0301. Should I install old coil pack as that was the one I removed.

When the car is idling rough:

• Listen to each injector for any differences from one to the other using a mechanic'* stethoscope or a wood dowel. You should hear a rythmic ticking sound which should be consistent from injector to injector.
• Disconnect the electrical connector from the fuel injector on cyl #1 and see if it makes any difference. The idle should get worse, or even stall out.
• Switch the injector to another position to see if the misfire moves to that cylinder
• If the misfire follows the injector, replace it.
• If not, use an automotive 12V bulb that has wires that can be extended and plugged into the electrical connector for the injector. Turn the engine over and see if bulb flashes regularly.

If you want to bypass everything above, just switch the injector on cyl #1 with an injector from another cylinder. If the misfire follows the injector, replace it.

Might have to take it to mechanic at this point which I was trying to avoid as I'm not working full time right now but I don't think I can do all the tasks referenced in the previous post. Are you thinking the fuel injector is bad? I will do the unplug test, if it stumbles and such does that mean the injector is okay?

If we accept this is a single cylinder misfire, and we have already replaced the coil, plugs and wires, the next suspect is the fuel injector. If you unplug it and nothing changes, it could either be a bad fuel injector, or the injector is not getting a signal to fire. More than likely it is a bad injector.

If is not a fuel injector, the next thing to do would be a compression test on all 6 cylinders to see if there is a mechanical issue.

My only concern is we are approaching this as a single cylinder misfire, as opposed to a random misfire, based on your scanner. I have seen where a cheap scanner will read a single cylinder misfire as random and vice versa. If it is a random cylinder misfire, the next step would be to check fuel pressure to see if the fuel pump is failing.

My diagnosis is only valid if the information provided is valid. I am absolutley not saying you are giving me incorrect information, just acknowledging the possibility your scanner may not be reading correctly.

I am starting to second guess myself. If the car is idling rough unplug the electrical connector to the #1 injector and tell us what happens.

Just to clarify, if the car is idly rough and nothing changes when you undo the electrical connector to the #1 injector, the injector is probably bad. If the idle gets worse, or the car stalls, the injector is probably not the problem.

One more thing to check. Undo the electrical connectors from all of the injectors, and check resistance across the two terminals for each injector. Report on the results. If the resistance on cyl #1 injector is significantly different that the others, the injector is bad.

I am still dealing with issues with this car. I'm still having issues at startup which happen most of the time after the car has been sitting for an extended period of time but recently has happened after a short period of time. The car starts and idles okay for a minute then it begins to stumble and almost stall out then the idle surges to around 2000 for several seconds and then settles down. Most of the time you can then drive with no issues but the car seems to shutter slightly or have a slight miss. This morning the car actually stalled when idling and I smelled gas. Code this morning was P0301, which has been a frequent code during this problem. I cleared the code and drove my son to school with no issues. In the late afternoon the car started and idled the same with the stumbling and surging issues as usual and when I put car in gear and started to go car seemed to take off on me for a couple seconds. Check engine light came on during the drive home and when I scanned I got codes P0300 and P0133. I have replaced both O2 sensors, fuel filter, plugs, wires, coil for cylinder 1 based on P301 code, IAC valve and PCV valve. I have also cleaned throttle body and ran 2 bottles of Techron concentrated fuel system cleaner through the gas tank. I just don't know what to do next. Thought the car was okay after I installed the IAC valve as it was good for about a week or two but problems came back as well as codes P0133 AND P1133 and my gas mileage went down so I changed the O2 sensors which seemed to cure MPG problem. I am desperately looking for help as I don't know what to try next and I'm currently not working and not sure I can afford to pay a garage to try to diagnose this and then make the repairs.
Please help.