stumbling on start up

Its time for a service. Most times(the last year) when I start it after sitting a day it has a hard time getting going. It will stumble for about 5 seconds really bad then it will run smooth. Sometimes its so bad I wonder if it will die, but it hasn't yet. Once started & warm you can turn it off & restart no problem. I have ran 1 bottle of chevron fuel cleaner & am half way though another right now. I thought it was helping but I dont think so now.

What does this sound like I need to do? I am going to change the spark plugs for sure but what else should I do?

93 crown vic 4.6L 29,800 miles. I think it has never been "serviced". So it has original plugs & wires.

What should I do? what plugs should I buy? I am thinking splitfire, what do you guys use?

Tom

If you tune the vehicle, use Motorcraft plugs and wires. Stay away from the gimmicks. As far as the stumbling while cold, check the idle air control motor. It is located in a really tight place on your car. It is down behind the engine just to the drivers side of the throtle body assembly.

add this to your list and check all vaccuume hoses and fuel pump. have you ever replaced timing chain? and how longs it been since you changed gas filter?

best we can remember nothing but the oil has ever been changed. for sure not the timing chain, maybe the gas filter but I don't think so.

I do not see or hear any lose vacuum hoses.

I am not sure how to check the idle air control motor or the fuel pump. If they were going bad would it have a code in the computer? I have a small code reader/tester I may try to run on it.

If the IAC is not damaged in the electrical portion, or the idle is not in the accepted range,(real low or high) it will not set a code. You can tap gently on the IAC with a screwdriver handle prior to starting and see if it helps the condition. The fuel pump has to be tested with a fuel pressure gauge. It will not set a code either.