Check engine light and "trans fluid -temp" light

KENWALLANDER

MEMBER
1994 ISUZU TROOPER
6 CYL
4WD
AUTOMATIC
194,000 MILES

This car came with all of the paperwork on shop repairs. It had a new transmission in 2006. I get a check engine light always, only after driving about twenty miles, or twenty minutes. Also only and always when driving up hills or steep grades. It is a hard light to have checked because it always turns off in a slowing to stop situation once my speed slows below thirty mph. Confused? I am. I will try to say it more clearly. The light always comes on, it is just a matter of the situation which I am driving. If it is flat grade, and my speed is over thirty five mph it will come on mostly always after twenty minutes of driving. If the grade is steep or filled with up-hills it comes on much sooner. The light will then shut off every time while slowing, once my speed falls below thirty five. I thought is was the transmission, but the fluid is new and full. I also though it could be the pressure behind the gas cap? It runs good every day, it is just the light concerns me. Also, I took it up a mountain for skiing and once in 4X4 I shortly after received a red "trans fluid hi-temp" light. What is going on? Please help!

7 Replies

MHPAUTOS

MECHANIC
31,938 POSTS

Hi there,

This sounds like you have clogged catalytic converter but we should run the codes to see what they are. Here is a guide that will help:

https://www.2carpros.com/articles/odb1-isuzu-1985-1994-cars-and-trucks-code-retrieval-procedure-and-definition

This guide can help as well:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please let us know what you find.

Cheers

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Monday, June 2nd, 2008 AT 10:07 PM

WDWEXPLORE

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0 POST

Thanks for this post! My catalytic converter was in pieces! All fixed more power than ever. ;)

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Wednesday, September 5th, 2018 AT 11:30 AM

JHOURIHAN

MEMBER
1 POST
1994 ISUZU TROOPER
6 CYL
4WD
AUTOMATIC
152,000 MILES

A few months ago I was driving on the highway and the check engine light came on for the first time. When the light was on, the car would run fine, but then it would go off and the engine would start to hesitate and the RPM's would go up and down. The light would come back on and the engine would run normal again. Nothing happened for a few months until this past weekend when it did it again. Same problem, and this time I noticed that my gas mileage took a big hit on the trip. I took it to a shop to have them get the code off of it, but there was nothing there, and the light will not come back on. Any idea what this problem could be? Thank you.

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Wednesday, September 5th, 2018 AT 11:30 AM (Merged)

KHLOW2008

MECHANIC
41,815 POSTS

Hi jhourihan,

Thank you for the donation.

Intermittent problem with no touble codes are never easy to diagnose and without the codes, it is imopssible to guess the source.

When CEL turns on, retrieve the trouble code without turning the ignition off.

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Wednesday, September 5th, 2018 AT 11:31 AM (Merged)

LLDEJESUS2002

MEMBER
2 POSTS
1994 ISUZU TROOPER
179,079 MILES

When we start the engine of the car, it does not want to run, we keep on and check engine light turn on and its start running a little bit better. I need to find that plug to scan the car.