95 CONCORDE HAS A SURGE UP TILL 100 KM

You can try a drive cycle, see if it helps? There may be an idle relearn, if just idle issue? Usually it will relearn idle on its own by driving.
Drive Cycle Recommendations:

1. Most OBDII monitors will complete more readily using a "steady foot" driving style during cruise or acceleration modes. Operating the throttle in a "smooth" fashion will minimize the time required for monitor completion.
2. Fuel tank level should be between 1/2 and 3/4 fill with 3/4 fill being the most desirable.
3. The Evaporative Monitor can only operate during the first 30 minutes of engine operation. When executing the procedure for this monitor, stay in part throttle mode and drive in a smooth fashion to minimize "fuel slosh".

WARNING
STRICT OBSERVANCE OF POSTED SPEED LIMITS AND ATTENTION TO DRIVING CONDITIONS ARE MANDATORY WHEN PROCEEDING THROUGH THE FOLLOWING DRIVE CYCLES.
For best results, follow each of the following steps as accurately as possible:
OBDII Monitor
Exercised Drive Cycle Procedure
Purpose of
Drive Cycle Procedure Drive Cycle
Preparation 1. Install scan tool. Turn key on with the engine off. Cycle key off, then on. Select appropriate Vehicle & Engine qualifier. Clear all DTC's/ Perform a PCM Reset. Bypasses engine soak timer. Resets OBDII Monitor status. 2. Begin to monitor the following PIDs: ECT, EVAPDC, FLI (if available) and TP MODE.
Start vehicle WITHOUT returning to Key Off. 3. Idle vehicle for 15 seconds. Drive at 64 Km/h (40 MPH) until ECT is at least 76.7°C (170° F). Prep for Monitor Entry 4. Is IAT within 4.4 to 37.8°C (40 to 100° F)? If Not, complete the following steps but, note that step 14 will be required to "bypass " the Evap monitor and clear the P1000. Engine warm-up and provide IAT input to the PCM. HEGO 5. Cruise at 64 Km/h (40 MPH) for up to 4 minutes. Executes the HEGO monitor. EVAP 6. Cruise at 72 to 104 Km/h (45 to 65 MPH) for 10 minutes (avoid sharp turns and hills) Note, to initiate the monitor: TP MODE should =PT, EVAPDC must be >75%, and FLI must be between 15 and 85% Executes the EVAP Monitor (If IAT is within 4.4 to 37.8° (40 to 100°F)) Catalyst 7. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period. Executes the Catalyst Monitor. EGR 8. From a stop, accelerate to 72 Km/h (45 MPH) at 1/2 to 3/4 throttle. Repeat 3 times. Executes the EGR Monitor. SEC AIR/CCM (Engine) 9. Bring the vehicle to a stop. Idle with transmission in drive (neutral for M/T) for 2 minutes. Executes the ISC portion of the CCM. CCM (Trans) 10. For M/T, accelerate from 0 to 80 Km/h (o to 50 MPH), continue to step 11. For A/T, from a stop and in overdrive, moderately accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to 64 Km/h (40 MPH) cruising for at least 30 seconds. While at 64 Km/h (40 MPH) , activate overdrive and accelerate to 80 Km/h (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 10 five times. Executes the transmission portion of the CCM. Misfire & Fuel Monitors 11. From a stop, accelerate to 104 Km/h (65 MPH). Decelerate at closed throttle until 64 Km/h (40 MPH) (no brakes). Repeat this 3 times. Allows learning for the misfire monitor. Readiness Check 12. Access the ON-Board System Readiness (OBDII monitor status) function on the scan tool. Determine whether all non-continuous monitors have completed. If not, go to step 13. Determines if any monitor has not completed. Pending Code Check and Evap Monitor "Bypass" Check 13. With the scan tool, check for pending codes. Conduct normal repair procedures for any pending code concern. Otherwise, rerun any incomplete monitor.
Note: if the EVAP monitor is not complete AND IAT was out of the 4.4 to 37.8° C (40 to 100° F) temperature range in step #4, or the altitude is over 2438 m. (8000 ft.), the Evap "bypass" procedure must be followed.Proceed to step 14. Determines if a pending code is preventing the clearing of P1000. Evap Monitor "Bypass" 14. Park vehicle for a minimum of 8 hours. Repeat steps 2 through 12. DO NOT REPEAT STEP 1. Allow the "bypass" counter to increment to two.
© Ford Motor Company

Need to take to a shop with a GM tech 2 or higher scan tool. These tools can actually display various sensor readings and voltages in real time and can be used while driving the car to recreate the issue. These are super expensive scan tools so most shops don't have them. Call around or bite the bullet and have a dealer do it. The money you spend on a correct diagnosis will be saved by not throwing random parts at it based on guess work.

Sensors in your wheels might need cleaning. They're magnets and rust can cover them sometimes.

there are a few things that could cause this , have you had the engine serviced regulary ?get the OBD codes read as may be the EGR valve or the Idle Control , clogged injectors , clogged exhaust , i'd try a fuel addative that covers the catalytic convertor as well as the engine parts , take for a longish run say 100 kilometers at a highish speed to get the engine to a good hot operating temperature

Check your tailshaft donut mounts

Sounds like you need to get your tyres balanced. If the vibration is when you don't touch the brakes only between the 80-100.
If its when you touch the brake pedal and the vibration occures, your disc brakes are warped, either machining or replacement.

indicates water in harness connections or at the terminals of the ECM or other modules

it could be a tei rod end or ball jouin or if it is rear wheel drine it could be a universal joint { hardy splicer } doing the wheels was a good start

Sounds like a possible vaccume hose leak?