The Powertrain Control/Emissions Diagnosis (PC/ED) manual has been revised for diagnosing electronic throttle bodies (ETBs). The ETC_ACT and ETC_DSD PIDs should not used to diagnose possible ETB concerns. The IDS has a limited refresh rate when reading these PIDs and cannot display quickly enough to validate a concern. The PCM automatically monitors these inputs more accurately and will set diagnostic trouble codes (DTCs) when appropriate. Using these PIDs for diagnostics will lead to inaccurate results and improper ETB replacements. If a concern is intermittent and no DTCs are present, refer to historical DTCs and the PC/ED, Section 3 No DTCs Present Index chart for further information.
full bulletin at NHTSA ↗2006 Mercury Montego engine problems
severe 13 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
13
Recalls
0
Avg fix
$3,100
1fire
When does it fail?
Of the 13 engine complaints filed for the 2006 Mercury Montego, here's the actual mileage breakdown — failures cluster heaviest at 25,000-50,000 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
No new NHTSA engine complaint has been filed on this vehicle in over 11 years — the issue may be aging out of the active population.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
FORD: SEE DOCUMENT SEARCH BUTTON FOR OWNER LETTER. MOMENTARY ENGINE IDLE RPM SURGE MAY BE INTERMITTENT AND MAY OCCUR, DUE TO DEPOSITS BUILDUP IN THROTTLE BODY, AT LOW SPEEDS, WHILE PARKING OR ENTERING DRIVEWAY AND CHECK ENGINE LAMP MAY ILLUMINATE. MODELS 2005-07 FREESTYLE, 500, MONTEGO.
full bulletin at NHTSA ↗MIL WITH DTC P0106 AND/OR P0109.
full bulletin at NHTSA ↗WDS COP KIT DIAGNOSTIC TIP - COIL ON PLUG (COP) IGNITION SYSTEMS - ENGINE MISFIRE OR ROUGH RUNNING.
full bulletin at NHTSA ↗ENGINE RPM FLUCTUATION AT HIGHWAY CRUISING SPEEDS - VEHICLES BUILT PRIOR TO 8/2/2005.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners report the 2006 Montego develops multiple engine-control failures that create unsafe driving conditions. Most common is sudden engine stalling during highway driving (50–60 mph), with check engine lights illuminating but repair attempts—throttle body replacement or computer reset—not holding the fix. One case shows stalling recurring twice after throttle body service.
Transmission behavior is equally alarming: owners describe violent, hard shifts that jolt passengers and can cause the car to lurch forward or backward unexpectedly, especially during highway acceleration. A dealership technician confirmed seeing this harsh-shifting failure often on Montegas.
Idle control is problematic. The engine runs too fast at idle and the car lurches suddenly when accelerating away from a stop, particularly when the steering wheel is turned fully. One owner reports this worsening over years despite computer resets. Another notes the lurch happens when shifting into drive or reverse, with engine revving to 1300 RPM.
Supporting failures include serpentine belt fracture at 60,540 miles (loss of power steering), transmission failure under 20,000 miles, and cylinder 5 failure at 30,000 miles. Service engine warning lights recur after dealer code resets. Mechanics report being baffled by the behavior.
Same Mercury Montego engine reports on nearby years: 2005
Failure modes owners describe
Engine stalling/sudden shutdown
Engine stalls without warning during highway driving (50-60 mph), check engine light illuminates, vehicle fails to restart or restarts but issue recurs. Some cases show throttle body replacement attempted but failure persists.
When: 48,942 miles; 60,540 miles; 62,000 miles; 85,600 miles; 170,000 miles
Symptoms owners cite: Sudden loss of engine power while driving; Check engine light illumination; Engine failure message displayed; Vehicle stalls at highway speeds; Failure to restart
Repairs/costs cited: Throttle body replacement (recurred twice after repair in one case); computer repair attempted in another case with no lasting fix
Recalls/TSBs owners mention: Manufacturer notified in narratives #3, #7, #9, #11; no recall issued
Harsh transmission shifting
Transmission shifts abruptly and violently, causing hard jolts that feel unsafe. Occurs during acceleration and highway merging. Dealer noted seeing this failure pattern frequently on Montego models.
When: Not specified in narratives
Symptoms owners cite: Hard/violent shifting from gear to gear; Sudden lurching forward or backward; Loud clunking noise during shift; Shifts out of gear during acceleration; Unsafe jerking motion during highway acceleration
Engine idle surge and lurching
Engine runs at abnormally high idle speed and vehicle lurches violently when accelerating away from idle, particularly when steering wheel is turned fully left or right. Issue persists after computer reset. Occurs across multiple model years and conditions.
When: Years of occurrence; problem worsening over time in one case
Symptoms owners cite: Excessively high idle speed; Sudden lurching forward or backward from idle; Violent engine surge when moving away from idle; Particularly severe when wheels are fully turned and vehicle is moving away from idle; Unpredictable jolting motion; Engine revs to approximately 1300 RPM when shifting into gear
Repairs/costs cited: Computer reset attempted but issue returns within a day; throttle body cleaning or replacement suggested
Serpentine belt fracture
Serpentine belt fractures during normal highway driving, causing burning odor and complete loss of power steering. Requires replacement.
When: 60,540 miles
Symptoms owners cite: Burning odor detected inside vehicle; Complete loss of power steering; Fractured serpentine belt visible upon inspection
Repairs/costs cited: Air compressor serpentine belt replaced at authorized dealer
Recalls/TSBs owners mention: Manufacturer notified; no recall issued
Transmission failure
Transmission failed early in vehicle service life at very low mileage.
When: Less than 20,000 miles
Symptoms owners cite: Transmission failure
Cylinder failure
Cylinder 5 failed during early vehicle operation.
When: 30,000 miles
Symptoms owners cite: Cylinder 5 failure
Check engine light / service engine warning
Service engine or check engine warning light illuminates; code reset at dealer but failure recurs.
When: 100,000 miles
Symptoms owners cite: Service engine warning light illumination; Check engine light illumination
Repairs/costs cited: Code reset at dealer
Recalls/TSBs owners mention: Manufacturer notified; no recall issued
Synthesized from 13 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
Tl* the contact owns a 2006 mercury montego. While driving approximately 60 MPH, the engine stalled without warning. The vehicle failed to restart and was towed to an authorized dealer for diagnostic testing. The throttle body was replaced, but the failure recurred twice after the repair was performed. The manufacturer was notified. The approximate failure mileage was 48,942.
Ac blows hot air when vehicle is not moving. If you are moving slow or stopped at a signal light or stuck in traffic the ac starts blowing hot air. It works fine as along as I am moving. *tr
When accelerating suddenly the vehicle would just shift out of gear, make a loud clunking noise and violently thrust forward and then back. It happens a lot when trying to accelerate onto a highway. It is very scary feeling. It is a sudden jolt. When we took the car to the dealership the repairman said has seen a lot of the harsh shifting failure with the transmission with the montego.
Had engine trouble with your 2006 Mercury Montego?
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 engine problem on the 2006 Mercury Montego?
It's a meaningful issue. 13 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Across the 11 complaints that reported odometer mileage, most engine failures cluster between 45,000 and 85,600 miles, with the median around 60,540. A quarter of owners report trouble before 45,000; a quarter make it past 85,600. 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 $3,100 for engine 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 engine?
No active recalls currently cover engine 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/2006/Mercury/Montego.
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.