Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 1999 Isuzu Trooper owners, lightly cleaned up (personal details are redacted by NHTSA).
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. Next time started RPM's at over 2, dropped when shifted to reverse, when shifted to drive vehicle accelerated without use of gas pedal up to steady 35 MPH on city street. …
I get frequent oil changes in my 99 Isuzu Trooper and had just gotten one last month. I had at least 2700 miles before my next one. I was driving down the freeway and I saw smoke coming from my hood and all my dash lights came on like a christmas tree. I pulled over and found out that my engine was on fire. I called the fire dept to put it out and got it towed to my house to later find out that the piston had got thrown from the engine because it locked up due to no oil getting to that piston. So now I have to get a new engine which cost about the same as the car.
I bought a 1999 Isuzu Trooper limited edition 1 year ago this month. Since buying it I have had the starter replaced, the alternator replaced twice, the small block was bad because of a failure with the dipstick to read the correct amount of oil. My son was involved in a mva due to the fact that the vehicle would not stop as the engine decided to race while he was coming to a slow stop. Thank god no one was injured in the accident. The car revs up at an idle at a stop or slowing down position, and now the vehicle is in the garage because the transmission is bad and the alternator went again. The front windshield is not properly sealed and the window fogs up if you don't run the defroster. The draft that comes from the floor on the drivers side is unacceptable. I bought this car with less than 30,000 miles on it and it now has less than 50,000. …
We bought a 1999 Trooper from the dealer that was never registered, but that the dealer had driven for 14,000 miles. We were told by the dealer that a new factory warranty applied as we were the "original retail purchaser." after driving this vehicle three years and less than 60,000 miles, the engine froze going up a mountain pass, endangering our lives and our grandchildren's lives. We had the vehicle towed and now have been told that we needed an new engine -- though there was still oil in the engine, there were shards of metal in the oil. …
I have a 1999 Isuzu Trooper that I purchased on 7/27/02 with 67,000 miles on the odometer. It now has 72,800 miles. It is a v6 with automatic transmission, and is in excellent shape. During my ownership, at four separate occasions, as I was coming to a stop at about the 5 MPH mark, the throttle has opened fully while in gear! I have had to "panic brake" the vehicle and push the transmission selector to "neutral". When I have done this, the engine has raced to 6000 RPM+ and held, so I have had to turn-off the ignition switch each time. After gathering my nerves, I have restarted the engine. The first three occurrences happened in traffic, so the problem has been a real safety concern. Last night, this problem happened in my own driveway. I nearly "took-out" my garage. After keying-off the ignition, I restarted the engine. …
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. We are paying to trailer the car to ks to have it checked by the dealer where we purchased the car and, presumably, the regional Isuzu representative. We are the original owners and the car has been serviced regularly; unfortunately, it's past the warranty period/mileage. There is no explanation for this mechanical failure but, a call to Isuzu of America, only had them say they've fulfilled their obligation. …
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. The consumer was told there was a problem with the frame of the vehicle and it could not be aligned. The tie rods were replaced because they were defective. In the past the vehicle lunged forward while the consumer had her foot firmly pressed on the brake. The vehicle intermittently idled high while stopped. The vehicle has rolled backwards while it was in park. …
1999 Trooper with 3.5l engine. After 60,000 miles I noticed that at regular oil change intervals, @3000 miles, that the engine was buring an excessive amount of oil. After an oil change, I drove from st.louis to kansas city, about 240 miles one way. On the return trip, 60 miles from home, the Trooper siezed up. No warning lights, no low oil light, it just quit. I had it towed to the dealer in st.charles and they told me that it had hardly any oil in the crankcase and that the engine was ruined. Several months later after listening to the price for an engine from the dealer $9500 and rebuilt engines that would take several months because blocks were not available, I with the aid of a mechanic found a Trooper that had been in an accident and replaced the old engine with one that had around 72K miles on it. It burns the same amount of oil!!!!!!! …
Sometime in February of this year, the engine failed on our 1999 Isuzu Trooper, possibly due to low oil. No warning lights or symptoms of any kind - vehicle just quit on route 95 in mansfield while my husband was driving home from bowling. Car was towed to local garage, where they confirmed that engine needed to be replaced - in fact, the tow truck driver had literally picked pieces up from the pavement underneath the vehicle. Upon searching for a new engine, we discovered that they were not easy to find unless purchased directly from Isuzu, and according to consumer affairs website, this is primarily because this type of failure is common among isuzus manufactured in late 1990's/early 2000's. Our regular mechanic, and several others questioned, confirmed that the Isuzu's were notorious for this type of problem. …
My orginal complaint #10104322 was submitted 11/04. Since then I have paid Isuzu and fox motor in grand rapids, mi about $7500 for a new engine. After many attempts Isuzu of America would not listen to me and even hung up on me. Fox motors was great. They advised the reason my engine froze up is a common problem with this engine. The EGR pipe gets clogged with "sludge" resulting in no oil getting from the bottom to top half of the engine. They advised to have EGR pipe cleaned and pcv valve replaced every 15,000 miles or one year. I'd like to sue Isuzu of America as I'm out a total of $8,500 due to, what I'm being advised, is a design failure in the early 3.5l v6 engines. It's obvious many others have incurred similar problems. I hope this suggestion by a "great" Isuzu mechanic is helpful to others. Fyi, I own two other isuzus (unlucky me!).
Engine complaints in other Trooper years
Frequently asked questions
How common are engine problems on the 1999 Isuzu Trooper?
NHTSA has 58 complaints about the engine & cooling of the 1999 Isuzu Trooper, 72% of the model year's 81 complaints. The component named most often is engine (29 mentions).
Is there a recall for 1999 Isuzu Trooper engine problems?
No. NHTSA lists no engine & cooling recall for the 1999 Isuzu Trooper. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 1999 Isuzu Trooper engine problems start?
Half of the complaints with a recorded mileage happened before about 71,000 miles, and 3% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 1 fire and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.