My check engine soon light is on and I don't know what to do. I had somebody check the computer and it showed a System is too lean error. What does that mean and how can I fix it. I feel the engine vibrating when my engine is idle and I don't what it is. I have a 1999 F150 and if anybody has a solution let me know.

Roel Salazar

 

System too lean, means that the engine is running lean, i.e. the gasoline and air mixture is off balance.

I don't know how to adjust that on a fuel injected engine though.

 

Hi Roel

Might i suggest when you post a problem here...on your 99f150

Post mileage on engine...Hey...could have 100,00mi. on it

List the trb. code that was thrown...i.e. PO171 etc....There maybe more than one code for lean burn...

Maybe someone here can be more helpful with the info. you posted?

Good luck....OT

 

that vib you have is most likely a miss. and if you have a miss. it will set a lean code. when you have a miss. there is more air going out of the exhaust. check your ignition sys. do you remember what the code is. or was there more the one. that would help alot. there are several type's of lean code's. it could help with finding the concern.

 

I would think that if you had a miss due to a misfire in the ignition system that you would get a rich condition due to the unburnt fuel from that cylinder. Now if you have a misfire due to an injector not firing you would have a lean condition...

 

I don't remember the code but I do know that it is two of them. All the book said was the system is too lean and so did the other code. My truck has 73,000 miles on it and it is a 99. I want to avoid taking it to a dealer without knowing what the problem really is. I had the injectors cleaned but that did not work. Does anybody have any other solutions.