BigRic Posted January 22, 2015 Report Share Posted January 22, 2015 My 98 Deville is beginning to have some issues, and I am both looking to find out what is wrong with it as well as determine if it is going to be worth fixing. I bought this car in January of 2011 for $1900 cash. Was in the market for a family car and actually walked past this car twenty or thirty times looking at other vehicles, all of which turned out to be crap. After finally driving this car, I was sold!!! It did wind up needing a tune-up, oil change, and tires --I was working at Rent a Wheel at the time and got some 18'' wheels and tires for cheap-- and after about five or six months the water pump went bad. Replaced that, and the car was fine for a while... I just recently replaced the heater core ( It was bypassed I assume by the previous owner) and noticed a slow leak in the passenger side of the radiator, which I replaced. I also replaced the torque strut mounts and coolant reservoir, as well as front rotors and brakes. The SES light came on right before Christmas, and pulling the codes I get two current: PCM p0420- Catalyst System Low Efficiency PCM p0741- TCC System Stuck Off (I know this one is bad and am considering replacing the transmission) What about the p0420??? Also, when accelerating I am hearing this loud grinding like noise which is new and is effecting power... The last issue is the car has progressively began to shake from the rear end and seems to sway from side to side... What do you all think??? I am fully prepared to do all work on this personally, albeit a bit slowly, if the car is worth soaking the money in... Any help/opinion is greatly appreciated. Link to comment Share on other sites More sharing options...
Göran W Posted January 22, 2015 Report Share Posted January 22, 2015 Any "HISTORY" codes? May be important. Link to comment Share on other sites More sharing options...
BigRic Posted January 22, 2015 Author Report Share Posted January 22, 2015 PCM p1560- transaxle not in drive, cruise disabled is the only one... Any ideas on the other stuff??? Link to comment Share on other sites More sharing options...
KHE Posted January 23, 2015 Report Share Posted January 23, 2015 The P0420 code would seem to indicate the catalytic converter is in need of replacing. Unless emissions testing is required in your area, I'd be inclined to ignore that code. The swaying in the back is probably due to worn out knuckle bushings. Grab the rear tire at the 12 o'clock position and attempt to move it toward you and away from you. If there is slop, the knuckle bushing are shot. Dorman makes replacements at a reasonable price. The torque converter lockup issue can be fixed at a reputable transmission shop for about $1200.00. If you drive it until the torque converter clutches start disintigrating, the debris will ruin the transmission. I don't know what the grinding noise may me. Can you get the car to make the noise if the car is in "drive" and someone applies the brakes while pressing on the accelerator pedal to brake torque the engine? If so, you may be able to listen with a stethoscope for the noise in the engine compartment. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
BigRic Posted January 23, 2015 Author Report Share Posted January 23, 2015 Thanks... I pulled on both rear tires, and they wobble pretty good on both sides. How much of a job is replacing the knuckle bushings???? No emissions here, was thinking of just cutting it off and being done with it, but not sure if it would hurt the car or not... The noise only happens when accelerating unless I feather the throttle. It slugs almost like a misfire, and the noise seems to be coming from the middle of the floorboard behind and underneath the radio, but not in the cabin. Once up to speed it's fine. Hope that helps... Link to comment Share on other sites More sharing options...
KHE Posted January 23, 2015 Report Share Posted January 23, 2015 The rear knuckle bushings are why the car handles squirrely. The worst part about replacing the knuckle bushings is removing the old ones. You will need to remove the knuckle from the car and then drive the old bushings out. An air chisel works well to drive them out. The Dorman parts include driver rings that you place on the bushings to drive them in place for the installation. You'll need to use Loctite on the toe link to knuckle bolt as well as tighten it with the suspension at ride height in order to reduce the wind-up in the bushings. Once you do this repair, you won't believe how well the car handles - it will be like new. I wouldn't cut off the catalytic converter - you will have more codes rather than just the efficiency code. I wonder if you may have a bad engine mount? The front mount takes a lot of abuse. Another thought is maybe some of the spark plugs are missing the platinum pad on the ground electrode. That would effectively open the gap and create a loss of power on acceleration. My STS had the P0741 code - it was intermittent for 50,000 miles, then constant for 12,000 miles before the clutches in the torque converter started to come apart. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
BigRic Posted January 23, 2015 Author Report Share Posted January 23, 2015 Yeah the code is coming and going currently, I cleared the codes and that one has not come back yet... About the knuckle bushings, how many are there???? Do you think all of them are in need of replacing???? Probably better to just replace them all but thought I'd ask anyway. Going to pull the plugs tomorrow at work and start there. Do you think that the plugs would make that awful noise though? Will also check the mounts, and no cutting the cat off. Thank you for all the info/suggestions so far and please do keep them coming!!! I will update everything tomorrow.... Link to comment Share on other sites More sharing options...
KHE Posted January 23, 2015 Report Share Posted January 23, 2015 The Dorman kit has two bushings - it will do one side. You will need two kits - do both sides. The plugs wouldn't make the noise - it was just a possibility for the lack of power. Maybe the exhaust is touching something under the car? It's hard to say. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
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