1999 Isuzu Trooper Problems

What owners report

Owners of the 1999 Isuzu Trooper most often describe engine oil consumption: oil disappears between changes, the oil light comes on late or not at all, and in many cases the engine then seizes or fails. Complaints cluster from roughly 40,000 to 80,000 miles, and several owners say they were told the oil use was normal. Lesser themes are engine stalling or idle racing, transmission failure, and a stuck accelerator.

1. 1
   Engine cooling

   Excessive oil consumption leading to engine failure

   • 40 complaints (49%)
   • median 71,500 mi at 6.6 yrs old (27 state mileage)
   • 1 mention a crash, fire or injury
   • owner-quoted repair $6,000 (median of 8 quotes)
   • filed 2000–2019

   Owners describe the engine using large amounts of oil between changes, in some cases roughly a quart every several hundred to a thousand miles, with no visible leak. Many say the oil pressure light never came on, or came on only after the level dropped drastically, and that the engine then locked up, threw a piston or rod, or caught fire. Dealers and mechanics reportedly replaced engines or piston rings in some cases, and in others told owners the oil use was normal for this engine. Some complaints attribute the loss to sludge blocking oil passages or a failed PCV valve. Mostly reported between about 40,000 and 80,000 miles, often after several years of regular 3,000-mile oil changes.

   What to check: Check the dipstick level and look for sludge under the oil filler cap; ask for oil-change records and how much oil the vehicle uses between changes. Having an independent mechanic check oil pressure and for a clogged PCV valve or EGR passage before buying is reasonable.

   2 excerpts from owner complaints in NHTSA records

   “From the time I bought the vehicle when it was only a couple years old, every time I brought the vehicle in for an oil change, they said it was almost empty of oil. I brought it in to a dealer several times since it was under warranty. They could never find the reason for it burning oil. Every dealer said it was a common issue with the Isuzu, but they could not fix it because they could not find the problem.”

   NHTSA complaint #10167797, filed 2006-09, 66,366 miles

   “While driving 70 MPH on a mi freeway, our car engine quit. Fortunately we were not in traffic and we were able to coast up an off ramp. Aaa trailered the 1999 Trooper to a former Isuzu dealership who, three days later, advised that the engine froze up and that we would need an entirely new engine. It should be noted that there was oil in the crankcase and that no warning lights went on until after the engine died. …”

   NHTSA complaint #10104322, filed 2004-12, 71,500 miles
2. 2
   Engine cooling

   Engine dies or stumbles while driving

   • 17 complaints (21%)
   • median 68,000 mi at 6.1 yrs old (7 state mileage, few)
   • filed 2000–2016

   Owners describe the engine misfiring, shuddering or cutting out while driving at highway or city speeds, sometimes restarting immediately and sometimes not. Several report repeated visits to the dealer where no cause was found, or an engine that lost power with no warning light. Reported at a wide range of mileages, including vehicles under 50,000 miles.

   What to check: Ask whether the stalling has been diagnosed or repaired, and request any stored fault codes. A test drive at both low speed and highway speed can help reveal a stumble or stall.

   2 excerpts from owner complaints in NHTSA records

   “Last 3 weeks - initially seemed like power loss/surge, then heard unusual sound coming from engine compartment 1 week ago, engine started to die while operating on city/residential streets whenever not pushing gas (slowing to turn or stop) friday, would not even hold idle to start, pushed gas and held RPM's at 1 - 1.5 for a while and finally started. Today, initially would not start. …”

   NHTSA complaint #10850767, filed 2016-03, 160,500 miles

   “Bought used 1999 Isuzu Trooper with 48,000 miles. Took it to mechanic because it had a problem starting. Discovered engine leaked more than 1 quart of oil per 1000 miles. Isuzu replaced engine just before 60,000 miles, but still has problem starting. Mechanic determined 3 or 6 fuel injectors are bad, and needed to be replaced. Trooper stalls at slow speeds, and engine will rev while idling.”

   NHTSA complaint #10078967, filed 2004-06, 50,000 miles
3. 3
   Vehicle speed control

   Engine races or will not return to idle

   • 12 complaints (15%)
   • median 74,500 mi at 6.9 yrs old (9 state mileage, few)
   • 2 mention a crash, fire or injury
   • filed 2001–2016

   Owners describe the engine revving up on its own when slowing or coming to a stop, or the pedal staying engaged so the vehicle keeps accelerating. Some say the dealer serviced the idle control or throttle but the problem returned, and in some cases drivers had to brake hard and shift to neutral or park. Reported from about 42,000 to over 160,000 miles, across mixed city and highway driving.

   What to check: During the test drive, let the vehicle idle and come to several slow stops to see whether the engine returns to idle smoothly. Ask whether the throttle body, idle control or pedal linkage has been cleaned or replaced.

   2 excerpts from owner complaints in NHTSA records

   “While driving the vehicle it began to surge as if it was stuck in high gear. The gas peddle seemed to be stuck and the vehicle started to go faster and faster. I applied the brakes and the tires screeched while the vehicle was still in motion forward. I shut off the engine and applied the brakes to stop the auto.”

   NHTSA complaint #10911340, filed 2016-10, 152,500 miles

   “While driving in traffic the accelerator pedal became hard to press then engaged and unable to control speed. All the while franticly applying the brake trying to release the accelerator, I had to force the vehicle into gear [park] where the vehicle then revved into the red zone before putting off. I then tried restarting the vehicle up and again the accelerator remained engaged [stuck] and would not release.”

   NHTSA complaint #10826011, filed 2016-02, 164,538 miles
4. 4
   Transmission and drivetrain

   Transmission failure or won't hold gears

   Mentioned in 4 of 60 sampled complaints

   Owners describe the transmission slipping, revving without moving the vehicle, or sticking in one gear, with metal debris found in the pan on inspection. Some reports involve replacement of the transfer case or more than one transmission replacement. Reported from roughly 25,000 to 80,000 miles.

   1 related service bulletin

   What to check: Check the transmission fluid for colour and metal particles, and drive the vehicle through all gears and up a hill. Ask for service records showing whether the fluid was changed and whether any transmission work was done.

   2 excerpts from owner complaints in NHTSA records

   “I purchased my Trooper new. I have all of the print outs of the oil changes made which are at or below recommended intervals. At approximately. 25000 miles I reported a shifting problem and they replaced the transfer case because metal filings were found in it. Then 2000 miles later the problem re-occurred and they replaced the entire transmission. It was bought in back 500 miles later for and adjustment on this again. At 40000 miles the cd player jammed and they replaced this with a new one that took 8 weeks to receive. …”

   NHTSA complaint #10013842, filed 2003-04, 74,180 miles

   “Isuzu Trooper 1999 problem after problem, engine burning oil. After the engine was replaced, the engine light illuminated at least 30 times. The dealer gave the consumer all types of excuses until finally they said they didn't know what was causing the light to illuminate. There were other problems such as a hard shift with the transmission, water leaking through the sun roof, difficulty starting the vehicle, uneven tire wear, in just 65,000 the consumer has gone through 3 complete sets of tires. …”

   NHTSA complaint #10113417, filed 2005-03, 40,000 miles

Buying note. The oil consumption reports are the main thing to look at on this model year, so ask for oil-change and repair history and have a mechanic check for sludge and oil pressure before buying. Verify that the power windows, transmission and idle behaviour are sound on a test drive.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.