i used the search feature but i didnt help much.i am working on my fathers 93 and the cel comes on and i checked it is a code 172.when i drive between 1200 and 2000 rpms the engine seems to flutter and i accelerate out of it.i pulled the plugs and the tips are white so i am in fact running lean.i replaced the cap,rotor,plugs,wires,02 sensor.no leaks found as far as i know it does not have maf.i am really getting no where with this.any ideas guys.oh btw the timing is dead ***** perfect.as far as injectors or fuel pump how would you test these or is there something else to check.please help!!!!!

 

Stored Code 172 and Run Code 172:
HEGO (HO2S) sensor fault/lean

If you just changed the 02 sensor and the problem still exists...check the wire going to the sensor and make sure it is not frayed or burnt.
When was the last time the injector system was cleaned?

With no Code 41 (always lean), and no Code 36 (lean idle), your O2 sensor is probably fine and you either have a clogged injector or a bad throttle position sensor giving bad data. It is also possible that you have developed a vacuum leak somewhere and your MAP sensor is reading incorrectly because of the leak. A squirt bottle with water or similar method with propane gas or carb cleaner will also help detect leaks.

 

to be honest dude i dont know if the fuel injection system has ever been cleaned.um also im not too sure if this model has map i think it has speed density.later today im going to recheck for leaks and someone told me to pay close attention to the intake area.ill let you know if i come up with something.

 

172 is the bad O2 sensor code, and if you just changed that sensor it may take a few drive cycles to go away. The basic actron pre-97 code reader also clears the codes, you just flip the switch while it's playing the flash pattern. When I replaced the O2 sensor on my 351(from CEL code), it didn't go away on it's own, I gave it like 3 days of driving. I cleared it with the scanner and it hasn't come back on since.

Clear the code and see if it comes back on again. You may have fixed the issue and the truck doesn't know it.

If it relights, ensure the harness connector on the O2 lead isn't corroded or damaged by exhaust heat.

And while I don't advocate leaning on "snake oil" fixes, you might want to try a bottle of good FI cleaner, or do some sea-foam thru the manifold vacuum.

 

mine turned out to be a vacuum leak, small tube on the manifold was cracked.

 

Glad to hear my opinions are not just hot air.

 

here is where im at.i replaced the upper intake gasket and the code is gone but the shuddering is still there so i had a theory and it looks like it holds true.i figured the code was for one problem and the symptom was another.so i drove the truck some more and it seams like the trans is shuddering.a little in third gear and worse in overdrive mainly between 1100 to 1500 rpms.so i did a trans service,dropped the pan and replaced the gasket and filter and drained the convertor the shifts are smoother but still shudders.i heard the
e4od is known for that when the torque convertor clutches start going bad so i guess i rebuild and convertor are in the works soon.