Re: help with a 2.5L
Sounds like you're truck is having the same problems my wife's Nissan Sentra has. For the last year or so, her car has shown horrible accelearation. It hardly accelerates at low rpms and then literally jumps up to speed at a certain rpm (no tachometer so I don't know exactly when). I tried a tune-up and $15 fuel injection cleaner, but neither helped. The vacuum hoses all look fine and are connected, and the motor runs great except for the acceleration problem. Also, the car's oil smells like gas every time I change it. This and some other stuff led me to believe the carb is running too rich.
I was going to change the air/fuel intake ratio, but I came to find out that it is all computerized. Fortunately, a salesperson/ex-mechanic informed me that if the O2 sensor goes out, the computer won't mix enough air because the computer thinks the engine is getting more oxygen than it really is. I called the Nissan service center and they confirmed this. Unfortunately, the sensor costs $70, but if it works, it's more than worth it.
Of course, my wife's Sentra doesn't have the timing problems you mentioned. Also, the lifetime on an O2 sensor is around 100,000 miles, so if your truck has considerably lower miles, I'd look elsewhere first. In any case, I'm ordering the sensor this Sunday. I should have it changed in two weeks or so and I'll post how it went for future reference. If you replace yours in that time, please let me know how it went.
[img]/wwwthreads_images/icons/cool.gif[/img] Steven Fairchild [img]/wwwthreads_images/icons/cool.gif[/img]
[img]/wwwthreads_images/icons/wink.gif[/img] <font color=green> 96' S-10 4x4 </font color=green> [img]/wwwthreads_images/icons/wink.gif[/img]