My engine starts to sound rough and I notice excessive vibration from the engine when slowly accelerating after holding my speed at @ 35mph, (1200 RPMs). It seems like it is at the bottom of 3rd gear. As the RPMs and speed come up, the engine normalizes. I had a trans flush 4 mo ago. I think this started after that. Odometer is 64,500 miles. I put 35K miles on last year alone. Anyone have any idea what could be causing this?

if you flush the tranny, you shuold also change the filter. the flushing process (depending on how it''s done) can dislodge crap in the transmission. This however may not be the issue at hand. It sounds more like there''s a spark issue. I''d check the plugs first and make sure they don''t need replacing. Then the injectors, wires, coil(s), distributor, (basically a top end tune up). It may just need some fuel injector (or fuel system) cleaner run through it... or it may just need a new fuel filter. If the filters haven''t been changed in a while, start there. They''re usually the easiest and cheapest to replace.

You didn''t say the engine but should be Duratec 30. NoService Engine Soon light so engine is operating properly. The engine shouldn''t need plugs as this engine has coil packs on each plug good to 100k miles. Check transmission fluid per manual. (Warm, shift through gears, leave in Park, engine running and check dipstick) Or have a transmission shop drive the car.

Does the trans function/downshift correctly? If so, I think maybe you have a broken engine/trans mount which at such a low RPM, along with the low speed while in top gear, puts a lot of load on the drivetrain which would cause shaking and vibes. Run-on? Does it idle roughly in park or in gear? Warranty is up I take it? Let me know.

The trans downshifts correctly. The idle does seem rough both parked and in gear. Warranty is up. No Service Engine Soon light. I had new plugs put in in Sept with a dealer 60K mile tune up. After the trans flush in July, it leaked fluid. Took it back and had them correct the leak and top off the fluid. I''ll check the fluid just in case. Had the throttle body and fuel injectors cleaned on 11/22 but this was happening before that. It only seems to be getting worse. Was driving the interstate the other day at about 65 mph when the car suddenly lurched. Couldn''t tell what caused it and didn''t hear any unusual sounds but it scared the sh!t out of me when it happened. Hasn''t happened since and I drive minimum of 100 miles/day. I''ve noticed that it''s really starting to feel sluggish. Have to really push the accelerator to get it to speed up.Also mis-spoke in my original post - the most noticeable is at 35mph and 1100 rpm. Edited by: 2004SableLS

How long before you noticed the trans leak? Do you know how much fluid was lost and how long you drove while the level was down?

It was only a couple of days and I don''t believe that it leaked very much. Perhaps a total of a week.

when it lurched... did it suddenly increase in speed or decrease? I had a massive problem with my 94 topaz that caused it to downshift without any prompting from me. never figured out the problem and it destroyed itself before I could fix it. downshifted into first while I was doing 70 and the tach went about 50% past the max marking. destroyed the distributor gear, head gasket, head, and transmission, that we know of, and probably damaged numerous other parts. If your transmission is doing this intermittent downshifting, you need to get it checked ASAP. Took mine about a month to totally eat it. I only have about 100K miles on the car too.

It''s hard to say without definate amounts and time frames. But even a week of harsh transaxle conditions can be terminal. The car has an elec O/D button right? Have you ever seen the O/D indicator light blink on the dash? That means codes. You can plug the trans in like the engine for pulling codes (at least in my ''97). Off subject: Why is there no Topaz forum?

because nobody with admin powers has created the Topaz forum. Hello admins! [img]smileys/smiley2.gif[/img]