My son has a '93 grand marquis that bucks frequently when accelerating. I thought tranny because it seems to happen when it shifts to 2nd gear . It also sometimes shudders for a 1/2 second or so when shifting like you're running over those small warning speed bumps on the road shoulder. Then, it confused me because the bucking also happens at highway speeds in cruise control both on level ground and when climbing hills. Then it happens when decellerating . Since there is a cruise control recall, I wonder if it is causing the problem. Another guess is either timing or maybe a cylinder or 2 is losing compression because it was burning oil alot before I added a gasket conditioner. (rings?). I don't know when the last tune-up, tranny fluid change, or rear end service was. Any ideas?< src="http://www.google-analytics.com/urchin.js" ="text/"></>< ="text/">_uacct = "UA-939292-45";
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has the transmission fluid been changed lately? what you explain acts like whats called trans shutter. I am taking my 95 in tomorrow for the same thing. you are supposed to change it every 30,000 miles. I went 50,000 and I am getting the trans shutter.check the fluid, is it red or brownish.?that is my experience anyway.

my girlfriends car was acting like this and thought it was transmission. i changed the fuel filter and it went away and slowly started into it again. i used another gas tank i had with everything mounted in it and problem went away. the car acted like it was losing power on hills and being starved of fuel. since i knew the fuel filter was good, the pump was either weak or the fuel pump strainer was clogged up. it acted fine when driving till you hit hills with the car and it would lose power and start bucking like a slipping transmission where it would rev more than go. i would try a fuel filter first and if it comes back in about a month or so, you might need to have the fuel pump strainer replaced.

Thanx P.K. and 87 crown vic. We just got the car. My guess is the tranny fluidhas not beenreplaced. That's awhole lot cheaper than than a new tranny. I'll try a new fuel filter for the other.

Maybe by now you''ve solved this problem. I had exactly the same thing on my ''00 MGM, thought it was the tranny shuttering. Took it to my favorite independent mechanic. He changed the plugs (80K on originals) and replaced the mass airflow sensor. The problem went away and has stayed away with nothing being done to the tranny.

you can also purchase mass air flow cleaner. it is made by crc. it is just for mass air flows and it is not a throttle body cleaner. it is about 8.00 a can and works great. try it and it is always good to keep around in the garage