just bought a 89 grand marquis, can anyone diagnose this problem?

[chefldawg]

The car runs fine. First thing I noticed is that it does this hesitation thing when it kicks into third gear. I figured it was just a tune-up problem. So i bought plugs, gapped them, and changed all the spark plugs. I noticed that it did run a little smoother but it still does that hesitation thing when it kicks into third gear (the car jerks until it goes into forth and its smooth again). I've also tried pouring fuel injection cleaner in the tank but it still happens. I'm also thinking I need a new muffler (the engine runs quiet, but the exhaust  is loud/rumbly ) because it looks really old and beat up. Are they easy to install yourself with sum clamps and wire hangers. I now its an old car but i know mechanics these days wanna charge you so much for a problem so little. Thanks for your time any suggestions would be appreciated.

[BradG]

It still sounds like a bad plug! Since they are new then check the plug wires! They act just like bad plugs when they go bad!

[ootsae]

check your transmission fluid level!

[shocked]

How's your tranny fluid?

[MoisesM]

doesn't sound like an engine problem but more of a tranny issue.  maybe fluid level is low or dirty.  doesn't sound like a little problem either. especially on an old car.

[Hammerhead]

Could be a bad COIL PACK, I'm not sure if your car has these but I have seen a bad coil pack cause this kind of problem on a 95 Crown Victoria

[JudgeSludgesays]

I have a 89 Lincoln T/C which is essentially the same car... Mine runs so great... I did have a hesitation problem, and an idling issue, and it would occasionally stall.... I did what was a fuel system servicing...My friend did it for me so I have no idea how expensive it would be to have done but I can tell you I have a new car.... it made that much of a difference...as for the tune up, that is always a good idea... Great car, good luck.