Isuzu SUV Forum banner
1 - 4 of 4 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter · #1 ·
I have a 92 Rodeo 3.1 5sp 4x4. I have been having a rough idle problem and can't seem to find it. So far I have replaced distributer, cap, rotor, TPS, idle air control, coolant sensor. Base timing is at 10-12 degrees. I have run fuel system cleaner a couple of times. Idling and running slight downhill when you are backed off the accelorator you can feel it not running smoothly. Under load it is fine and it is getting about 20 mpg. If I unplug the MAP sensor while idling it will smooth out, plug it back in and runs rough.

Any ideas?
 

·
Registered
Joined
·
13,615 Posts
Maybe that sensor is giving a bad reading. Take a drop light and shadow the injectors in the throtle body, look for the spray pattern. One might be plugged up and giving only half the spray. Injector cleaner won't or can't cure a bad injector. If you can get o ring kits for them you might be able to pull them and have them serviced and or check the screens.

Welcome to the planet !!!
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #3 ·
Thanks for the info. The injectors are putting out a good spay pattern. I got a rebuild kit and rebuilt the throttle body this afternoon. It wasn't too bad but now it is all cleaned out and has new gaskets on everything. I also had another map sensor on my 93 pickup that I switched over. The idle is better but not where I think it should be. One of the locals here said that I may need to drop the tank and check all the small rubber lines in the fuel pump could be leaking not holding pressure. I did notice that when I broke the gas line loose there was no pressure on the line and I had just driven it home. Should there be pressure in the system after shutting it off and setting for a few minutes?
 

·
Registered
Joined
·
13,615 Posts
It should hold pressure for quite a while. Not sure if there's a pressure tap to check on that one. You might have to buy a T and plumb it in.
 
1 - 4 of 4 Posts
Top