intermittent problem with throttle

I just recently bought a 2001 isuzu trooper s 4wD with about 60,000 miles on it. The truck ran smooth for a few days but sometimes will idle all the way down to 0 RPM and then die. Sometimes it sets a check engine light and also a reduced power light. I had the codes read P1125 and P1515 both seem to be symptom codes of a problem with the signal the electronic throttle is recieving, I had the carbon and dirt build up cleaned out of the throttle body, no help. I have a strong suspicion this is a throttle position sensor but would like to hear suggestions before i buy the part and replace it. Any advice would be appreciated.

Sounds like a classic Intake manifold gasket problem See the FAQ's.

It could be TPS, but these rarely fail (there was a recent post, the part costs 50 bucks shipped from St. Charles Isuzu).

Hello,
I check both codes from the factory service manual for your isuzu and it points to your engine coolant temp sensor. i would replace this first before you do any thing else.
Good Luck
Help was offer by www.usaimportparts.com

I originally thought this was the problem, but the shop that did the throttle service did check the IMG's for leaks...none found. I haven't been able to actually hear a leak either and i did the carb spray test no increase in idle. Also with an IMG there is usually some type of Lean Bank code or oxygen sensor code because the IMG leak causes the fuel mixture to be off and these codes aren't present. At least thats what the tech was telling me, of course when i had it at the shop the vehicle was running fine and he couldn't pin point the exact problem with out duplicating what the vehicle was doing...imagine that. He managed to charge me $125 though.

Where is the engine coolant temp sensor located? That info is different from mine. I referenced those codes with Alldata and they suggest those codes are set by either a bad signal from the tp sensor or a bad signal from the acceleration pedal sensor

I purchased the tp sensor from St. Charles, they were great by the way, and i'm going to install it tonight after work. I'll report back after i find out if its the fix or not. Thanks.

It's been a week and no problems since replacing the tp sensor