Alright guys I'm a little new to the truck world but I have some knowledge.
I have a 98 f150 5.4xlt and tonight on my way home my truck started to feel as if it was wobbling when I was in park. I idled to about 4 grand and it stopped. I'm not to sure what it is. Also I got 69 blinks from my CEL. I just put new tires u joints and driveshaft on. Any suggestions?

 

If the CEL is blinking, that means you have a cylinder misfiring.

 

@JCR 56, certainly no malice intended and I hate political correctness too. But in the interest of promoting good diagnostics logic (absent of jumping to conclusions), a "blinking" CEL does not specifically mean a cylinder is misfiring.


Specifically it means the ECU has determined the fuel/air ratio, as determined by O2 sensor voltages AND time, is so RICH as to be potentially catalytic converter damaging. Too many misfire events, due to the unburned fuel being expelled into the exhaust, will certainly produce that condition. And in @Ford_Guy_36 's case, I suspect you might be "RIGHT". But my point is - it is NOT correct to emphatically say a blinking CEL MEANS a cylinder misfire.


I do not know what "wobbling when I was in park" means. But I do know new tires, u joints and driveshaft has NOTHING to do with the flashing CEL. But winding it up to 4 grand in park raises several possibilities, only one of which would be misfires. In a 98 model with unknown mileage or condition could be sticking / sticky fuel injectors, engine blow-by, old / lazy O2 sensors, bad MAF sensor, or clogged cats. OR possibly cylinder misfires. But it definitely means the ECU "THINKS" the exhaust gases are VERY rich.

And the condition should be fixed soon or it will ruin the CATS

 

That being said, I still think he has a misfire, but we'll probably never know since the OP seems to be one and done.