Update on odi number 10208094. On the day the mercury that I own was returned to the dealer to solve the safety problem, an accident occurred within 10 miles of my home. The vehicle was a late model Lincoln town car. One person was pronounced dead at the hospital and the driver died a few days later. The following is a quote from the next day brevard county florida local newspaper (florida…
2008 Mercury Grand Marquis cruise control problems
critical 14 complaints filed with NHTSA · avg repair $600 · see cruise control across all vehicles →
Failure mileage
Complaints
14
Recalls
0
Avg fix
$600
5crashes
1fire
4injuries
2fatalities
When does it fail?
Of the 14 cruise control complaints filed for the 2008 Mercury Grand Marquis, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Among the 5 model years of Mercury Grand Marquis in our records for cruise control problems, this one ranks #3 by owner-complaint volume.
No new NHTSA cruise control complaint has been filed on this vehicle in over 18 years — the issue may be aging out of the active population.
The failure pattern owners describe
Owners report sudden unintended acceleration in their 2008 Mercury Grand Marquis, often paired with cruise control use or brake application. The pattern is consistent: vehicle revs sharply—sometimes to 4,000–5,000 RPM—and surges forward despite the driver's foot on the brake. Incidents occur at low speeds (reversing out of driveways, stop-light braking) and highway speeds (65 mph), with owners hearing an audible clunk from the engine compartment in at least one case before normal operation resumes. Multiple owners report the problem resets if they shift to neutral, kill the engine, and restart. Several instances resulted in crashes, with one fatality mentioned in a related Lincoln Town Car. Dealers consistently claim they cannot duplicate the failure and often dismiss owner reports as simultaneous brake/gas pedal depression. One dealership replaced the ECM after an 80 mph surge. Low mileage at failure (500, 4,500, 17,869 miles) suggests the issue emerges early. Owners emphasize the problem is not operator error and express genuine fear about vehicle safety."
Same Mercury Grand Marquis cruise control reports on nearby years: 2005 · 2006 · 2007
Failure modes owners describe
Unintended acceleration during cruise control engagement or brake application
Vehicle suddenly accelerates to high RPM (4,000–5,000 range) when driver applies brake or resumes from cruise control, causing violent forward surge despite brake pedal depression.
When: Early in vehicle life; reported at 500, 4,500, 17,869, 27,500, and 42,000 miles; also on used purchase with unknown prior mileage
Symptoms owners cite: Engine revs sharply to 4,000–5,000 RPM when brake applied; Vehicle surges forward despite brake pedal depressed; All warning lights illuminate on instrument panel; Audible clunk from engine compartment (one report); Rumbling sound and vehicle vibration; Problem resets after shifting to neutral, killing engine, and restarting; Occurs both at low speeds (reversing, stop signs) and highway speeds (60–80 mph)
Repairs/costs cited: One dealer replaced the ECM; most dealers unable to diagnose because failure cannot be reproduced during inspection. Body damage was repaired in crash cases. Vehicle traded in by at least one owner.
Engine ramp-up on cold start or after extended soak
Engine revs to estimated 4,000 RPM with loud rumbling and vehicle vibration after vehicle sits for 22+ hours; resolved only after multiple restart attempts and key removal.
When: After approximately 22 hours of soak time
Symptoms owners cite: Engine revs to 4,000 RPM on cold start; Loud rumbling sound; Vehicle vibration; Requires multiple restart attempts; Resolves after key removal and reinsertion
Repairs/costs cited: Dealer stated no repair possible without service light illumination. No diagnostic performed.
Synthesized from 14 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 2 most recent
False acceleration of 2008 mercury grand marquis. On oct. 9th, my wife and I and two friends (from pa and de) were in vehicle headed for dinner. Cranked vehicle after setting for approximately 22 hours. Engine revved up to an estimated 4000 RPM created loud rumbling sound and vibrated vehicle. I was too frightened to look at tachometer. Turned switch key off. Made 3 attempts to start engine.…
Had cruise control trouble with your 2008 Mercury Grand Marquis?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the cruise control problem on the 2008 Mercury Grand Marquis?
It's a serious issue. 14 complaints have been filed, including 5 reports involving a crash and 2 fatality(ies). We've classified it as critical based on NHTSA's reported outcomes.
At what mileage does the cruise control typically fail?
Across the 11 complaints that reported odometer mileage, most cruise control failures cluster between 4,500 and 78,013 miles, with the median around 39,000. A quarter of owners report trouble before 4,500; a quarter make it past 78,013. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $600 for cruise control repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to cruise control?
No active recalls currently cover cruise control issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2008/Mercury/Grand Marquis.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.