When driving on slight incline with steady throttle between 50 and 65 mph
(85-110 kph) have shudder, let up or increase gas lightly, shudder goes away. Wheels/tires checked OK, new plugs and wires?? Have heard possibly TCS??

Any help appreciated.

sounds like plugs and wires to me.

Sorry to be confusing, I have already changed out the plugs and wires to no avail. Symptoms remain the same. Does not matter whether I am in 4OD or 3 gear symptoms the same with exception of speed during shudder slightly different. As stated, have had the wheels and tires checked for balance and RFV. Usually happens on an incline, but can make happen on a straight stretch occasionally.:rolleyes:

Check your EGR valve

Just a thought

Andy

I'm going to say it again PCS solenoid! If you have a 4T65E transmission the PCS is the source of your problems. It is a known problem with this engine and every tech should know about it. It havs been a GM bulletin for years now and if an Indy shop has Alldata or Mitchell they should also know about it!

Flatrater, when you state PCS is that the same as the Pressure Regulating Solenoid listed at Alldata?

Shudder is gone!!!!

Problem arose after Transmission shop serviced my transmission. I did the standard checks of wheel balance, misses etc. Scoped the engine both in the shop and on the road. Put in transmission additive and the shudder moved to different speed(numerous speeds). Went to GM dealer, they could not initially find shudder. Took them on road test and they told me replace TCC. Big dollar quote. I thought as previously suggested PCS.
In desperation, before spending large dollars on tearing apart transmission, had a different transmission shop(after they found the shudder, but were loath to suggest replacing TCC) flush, change filter and refill transmission with quality fluid. Low and behold, the shudder has gone away??
First transmission shop stated they would be very interested to see if the shudder came back. Three weeks of highway driving later, and still no shudder. So much for dealing with a "quality" shop that is not the dealer.
Thanks again for all the help you folks offered me on this thread. Your comments where instrumental in saving myself a large expense.

what did you replace to get rid of the shutter? was it the pcs solenoid or did just changing the fluid and filter do it? My 99 gs is doing the same thing. I already had the tranny flushed and filter.

any info would be greatly appreciated this problem is driving me nutts...

I have a 98' regal Ls same problems... I am actually thinking of selling the car over it.. it began as harsh shifts.. I noticed some slipping here and there and then that went away.... next it seemed as though tranny was shifting into 4th/ or locking torque coonverter just above 30 mph.... and also staying locked till nearly stopped.... this caused nudging or lurging feeling slowing down through 20 and then especially when touching gas again to speed up (usually turning corners)... The lurging has been harsh enough to cause check engine light to come on... but all went away for a week or so... back again yesturday... What should I do? Also not sure if it means anything could have been shot over my neighbor's lawnmower or something but I found a 3-4 inch with slant part... looks like rubber tube....in driveway... could this belong to my car.. and are there any parts like this that would cause such problems if loose or missing?

To you guys and gals who have harsh shifting in your 98-99 Regal or LeSabre, the PCS needs to be replaced. This will fix any harsh shifting and the "jolt" when shifting into reverse from park when cold. My 99 LeSabre had these symptoms and after having the PCS replaced, they went away and it shifts very nice now. BUT! The shudders are there now at around 45-50 mph and 1400-1500 rpm on flat to slight incline roads with slight acceleration. I have been told to check the CV joints for any play in them too. I am going to take it to AAMCO tomorrow and see if they can remedy the problem. The transmission is the famed 4T65E. Is there anything else I should have checked?
Thanks.

What did AAMCO say. Is your problem cured?

well, GM is replacing the transmission after a long drawn out battle with them. The tech at the dealership found metal shavings in the cherry juice and has deduced that the Sprag gear is most likely on its way out along with the torque converter. It would be cheaper to replace the whole tranny instead of rebuilding the old one.

Should ride an d drive like new...I hope...

I was having a similar experience with our '93 Regal, shudder on acceleration and a missing feeling when pulling a hill in OD. Tranny fluid OK, new sparkplugs and wires, new fuel filter; all made no change. Finally replaced all three ignition coils and problem is gone....so far! Probably was just one of the coils but, what the heck, with 150,000 miles I decided to replace all three and save the time and trouble of diagnosing which one might be bad. Maybe this will help somebody.