1999 Isuzu NPR Repair Question
Mileage: 78,000 miles.
Can't drive truck over 50mph. No acceleration at all. After a while truck stalls. Fuel filter problem?
Could it be the fuel filter? The ERG valve? Clogged fuel lines? Exhaust flap getting stuck?
Any help you could provide would be greatly appreciated. Thank you. Marc
Asked by mgarrardAnswer
There are a few possibilities and the fuel filter is might be partially clogged as the engine is struggling when you increae the speed.
Reduce the driving speed to see if there are any changes.
After waiting 40 min last night I was able to drive the truck 50 miles back to my house without any problems. I didn't try any rapid accelerations or try to top out the speed for fear of having any problems. I just wanted to get home.
This morning I drove the truck to my job site and did not have the same problems I experienced last night. The only thing I noticed this morning was a knocking noise upon acceleration. It was coming from the driver side and sounded like it was coming from the exhaust/muffler area. This only happened one time.
Now I am sitting in the truck idling with the AC on and I can smell the fumes. The AC is on recycle so I shouldn't be smellin the gas fumes.
Hopefully this provides you with the information you are needing. Where should I begin with the trouble shooting process? Thank you again for your assistance as I just spent my hard earned $6000.00 and can't afford to spend another $1,000-3,000.00 on repairs.
Let me add that just now when I got out of the truck I heard that knocking noise coming from the catalytic converter. Could this be my dilemma?
It is possible the catalytic converter is bad and this can result in the knocking noise you are hearing. It can also cause the inability of high speed driving as knocking noise form the catalytic converter can mean it is dislodged internally and cause partial blockage of the exhaust system.
You would need to remove it to check. A viausl inspection might tell you something.
When the catalytic converter fails, it would usually throw a code. Is the MIL indicating and have you checked for trouble codes?
Yesterday (Tuesday) I drove the truck for the first time since arriving in Phoenix. The check engine light kicked on and stayed on the entire time I drove the truck. At stop lights the truck would go from idling as if the engine wasnt even running (which is great) to choking every 10 seconds or so. The choking made it feel like the truck was going stall. It had me in a panic everytime I came up to a light.
So, I stopped by O'Reilleys and had them check for a code. It said it was an issue related to the catalytic converter. I took the truck in to a muffler shop and they installed two new cats. The one cat was completely wasted inside and definitely needed to be replaced. After an hours wait...voila...two new cats and I was back on the road. I thought my problems were resolved! NOPE!! Read on...
Once again the truck acted as if it wanted to stall at lights! Then as I was exiting the freeway, the truck decided to stall completely as I pulled up to the light. I couldnt restart the truck so I exited the truck and gave it 5 minutes. I went back to the truck and started it up. I drove straight to an Auto Zone. I spoke with one of the guys and described my problem. He said it could be a fuel filter, fuel pump, a sensor, a vacuum issue, etc. I purchased a fuel filter and I am going to start with that. While I am in there I am going to check the spark plugs as well.
Does anyone have any other suggestions or recommendations? Thank you for your help!
Check the fuel pressure and if the idling was too low, have the throttle body and IAC cleaned.
Other than that your planned course of action should be sufficient for now.