Scotty,
I have had a 1997 crown Vic since 2018. It has the good old Ford 4.6L V8 and the 4 speed automatic transmission with overdrive. In terms of maintenance I have changed the plugs, radiator, hoses, water pump, and I change the oil every 4000 miles. It has 239k miles will all original power train. It runs like a top, but occasionally at high speeds I feel the car shudder and vibrate. I don’t know if the alignment is bad, if there is a slight misfire, or if the transmission is slipping or going out. Thoughts?
Hi! Nice care you have there!
I think you should go through the basics. If you're braking at high speeds then it might be uneven disc brakes if you have any, or the rotor disc is uneven. Or needs cleaning. A wheel balancing too. Uneven tires as well. I hope it's just one of those things. Not the high priced stuff.
Have you replaced the fuel filter lately? If not, then start there. Could also be that your fuel pump is getting weak. Check the air filter too.
If the check engine light is not on and you aren't getting any codes, then you might need a wheel alignment.
