Have an '11 Crown Vic with 280k that's been used as a delivery vehicle most of it's life. Just got it so I'm not too familiar with it's history.


Two days ago I noticed at idle the engine had a variable missing / jerk shaking pattern, but otherwise drove fine. Next day the driving is much rougher. It seems to miss somewhat going through the first 3 gears but it's manageable with varying gas pedal. It's not until you get into O/D that things really start to shake. Soon as it switches up the whole car goes into a rumble. You either have to let off the gas or press harder, as acceleration seems to calm it down some. Engine light is permanently on and flashes when the rumbling is at it's worst. Wish I had some codes to quote but haven't had a chance to get it hooked up yet. Mechanic who I gave a ride to yesterday said it felt like a bad oxygen sensor. I asked if it could be an injector and he said the missing would be more consistent if it was.


I'll be getting it read asap but in the meantime thought I would get yalls thoughts on it. What else could it possibly be other than an O2 sensor?

 

Not knowing it's history, you have to start from the beginning.
Spark plugs?
Fuel filter?
Coils?
You gotta start someplace ! The codes will help provide some direction
If the C/E light has been flashing for any period of time you may wind up replacing the converters after the original problem(s) are corrected. And that gets pretty expensive.

 

Start at the beginning most definitely. If I'd had more time a lot of stuff would have already been replaced. Hopefully I can get most of that done before things get too cold.

What is this about the c/e light flashing? This is the first I've heard the term converter. What is it please?

 

Let's hope I can do this right !

When the engine exceeds the permissible allowable emission from the tail pipe the job of the check engine light is to notify the operator there is a problem.
If the light comes on steady a code is usually stored in the engine computer and follow up should be done to determine why.
When the check engine light is flashing it indicates there is a serious emission problem which if continued can overheat the catalytic converter(s) causing them to melt internally and rendering them useless and non functioning. That will produce a code that is dreaded because it can get expensive to correct.
When the initial unburned/ overfueled problem is repaired/corrected the converter code can show up and the bank account starts to suffer.

Anytime the check engine light starts flashing, have the vehicle checked out because if not corrected or the light goes out by itself, excess hydrocarbons (fuel) cause the converter to overheat trying to clean up the emissions.and if ignored ,, well that's when $$$$ develops wings.

 

Oh ok...cat converter. What's the expensive part, replacing the cat?

 

NO, Paying for it !!