2003 ford police interceptor rough running?

I'm buying a used 2003 police interceptor today. It has low gas because the dealer obviously keeps it low. The engine runs strong but a little but rough when I'm at a traffic light. When I drive it's smoothest and goes away. Nothing is leaking with pressure hoses and stuff. Should I just throw injector cleaner in it? Any special gas when I go to fill it? Let me know

How come people hate dodge?

Why does everyone hate dodge? I have a 1999 dodge ram 1500 5.9 magnum and while i've owned both ford and dodge its the ford owners who hate dodge… Why? Dodge are great and mostly the people that abuse them and don't give the proper maintenance required are the ones who get disappointed with them and well ill be honest i do abuse my truck sometimes ill say that dodge engines are bullet proof while there transmissions are not big enough for the power they make is why they break. Also the bad rap on the 5.2/5.9 magnums not making much power unless you have driven one you wouldnt know that these engines are torque monsters especially with a m1 intake and a tune youl be in the mid 300hp and peaking in the 400tq range. They are great motors i see more ford rusted out than i do any other vehicle much like toyota i have owned chevys and while they are good too they just don't look good anymore they look like a 3 year old etcha sketched and truck and they went with that design.

So why does dodge get such a bad rep?

Should I buy a 2007 Ford Crown Victoria?

I'm thinking of buying this car and putting a push bar and a spotlight, no tinted window or cop signs, and also the car painted all black… Can I do this or not?

1989 Ford Crown Vic locks, seat belts, and corrosion?

Okay I just got a 1989 Ford Crown Vic she is nearly perfect except the lock on the driver side doesn't work at all automatically or manually and the lock that I'd push to lock it from the inside feels very loose and the key won't turn in the door

The seat belt are very loose they don't retract hardly any

3 there's alot of corrosion on the battery now I heard the coke thing poorig it on helps but how long do you keep it on and would Dr. Thunder (a generic Dr. Pepper) work just as well?

If someone could help me figure out how to fix these things that would be great my Dad said its an easy fix but he didn't tell me how to do it so if someone could help me that would be great

Added (1). And now the battery is dead and jumping isn't helping

Yet another Q about an old Windstar?

1995 Ford Windstar but the previous owner replaced the engine, (from a Taraus or something?)
Don't know if it was rebuilt or salvaged but I've owned it since 2006 and it is a champion. 3.8 liter V-6 put in sideways (Doh!) because front wheel drive.

At idle I'm getting a low oil pressure idiot light. I turned up the idle a little and it's been months since I;ve seen that light come on while waiting at stoplights but now it is happening again, on occasion. It's intermittent, only happens once in a while. Someone mentioned it may be a lose timing chain issue but that makes no sense to me, how that could be related.

Also, I have a secondary issue. Had the auto transmission completely rebuilt 3 or 4 years ago by a very reputable shop but now every couple weeks it has trouble finding and getting into 2nd gear. After a minute it is fixed and doesn't happen for another couple weeks.

All fluid levels are correct.
So what's going on? Is my oil pump failing? Is the trans getting confusing signals from the engine computer? I drive this car very gently and it seems that my feather touch on the throttle is when the tranny acts weird, but if I drive it hard it works fine.

Your opinion as to cause(s) and should I just take it to the Ford dealer and pay (use to be) $75 for a diagnosis? I can't get to the oil filter because it is up against the firewall.

Added (1). EDIT: 3d question: the darned warning sound comes on now that the weather is warming up, apparently it thinks a door is open. I have tried the Wd-40 on the sliding door contacts and that worked well all winter but now it's doing it again. How can I make that noise stop?