help me please
#1
#2
RF Veteran
iTrader: (1)
CEL(check engine light) is the computer giving the driver a "heads up" about some parameters that are out of range.
While the codes are helpful they are not to be taken literally.
Ignore P1445 for now, it is for gas tank ventilation
What are the symptoms?
The 030x codes are misfires, do you feel any misfires?
Are they at idle only or at higher RPMs as well?
The 171 and 174 are Lean codes and are often associated with vacuum leaks, but it would have to be an upper intake vacuum leak to effect BOTH sides of the engine(bank 1 and bank 2).
MAF sensor may need to be cleaned, also check the air tube from MAF to intake, if that is leaking air then same "lean" codes come up.
If possible check fuel pressure, low fuel pressure is the same as too much air as far as the computer is concerned.
Lean code means there is too much oxygen in the exhaust, NOT to little fuel, O2 sensors can only "see" oxygen.
If a cylinder misfires, then all the air(oxygen) is not burned with the fuel, it is just dumped into the exhaust manifold and O2 sees it as Lean.
So the misfires could be causing the 171 and 174 codes
And an air leak could be causing an actual Lean condition so you get the misfires.
While the codes are helpful they don't pinpoint the problem.
Old spark plugs or a failing coil could cause misfires, and the lean codes.
I would check the spark plugs, all of them, see what they tell you about conditions in each cylinder, keep track of which plug comes from which cylinder.
Google: Spark plug condition
Good visual images of what spark plug tips can tell you.
You can even get some "bad" gas(has water in it) that will cause the misfires and so the lean codes with it
While the codes are helpful they are not to be taken literally.
Ignore P1445 for now, it is for gas tank ventilation
What are the symptoms?
The 030x codes are misfires, do you feel any misfires?
Are they at idle only or at higher RPMs as well?
The 171 and 174 are Lean codes and are often associated with vacuum leaks, but it would have to be an upper intake vacuum leak to effect BOTH sides of the engine(bank 1 and bank 2).
MAF sensor may need to be cleaned, also check the air tube from MAF to intake, if that is leaking air then same "lean" codes come up.
If possible check fuel pressure, low fuel pressure is the same as too much air as far as the computer is concerned.
Lean code means there is too much oxygen in the exhaust, NOT to little fuel, O2 sensors can only "see" oxygen.
If a cylinder misfires, then all the air(oxygen) is not burned with the fuel, it is just dumped into the exhaust manifold and O2 sees it as Lean.
So the misfires could be causing the 171 and 174 codes
And an air leak could be causing an actual Lean condition so you get the misfires.
While the codes are helpful they don't pinpoint the problem.
Old spark plugs or a failing coil could cause misfires, and the lean codes.
I would check the spark plugs, all of them, see what they tell you about conditions in each cylinder, keep track of which plug comes from which cylinder.
Google: Spark plug condition
Good visual images of what spark plug tips can tell you.
You can even get some "bad" gas(has water in it) that will cause the misfires and so the lean codes with it
Last edited by RonD; 04-07-2015 at 11:04 AM.
#3
Check your lines going to the EGR tube. I had P0171 and P0174 for over two years. I could not find any vacuum leaks. Checked/replaced multiple hoses, sensors, etc. I had a friend looked under the hood and in 2 seconds he noticed one of the lines to the EGR tube had moved up a little. I pushed the line back down and have not had any troubles for 3 months now. Mileage went from 11mpg to 18mpg. I lucked out, sometimes it's the simple things.
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