P0106 Ford - escape hybrid

Question

I have a 2005 Escape hybrid. I'm getting two codes, P0171 and P0106 and my fuel mileage is off by about 30%. I have a scanner that allows me to monitor the sensors real time. At idle (~1000 rpm). LTFT is around 4 to 5%, STFT is at about 3%. Increase the rpm to 2500 and LTFT remains the same, no or very little change, STFT jumps around between -2% and + 1.5%. Put it in drive and accelerate and the LTFT jumps to between 25 and 30%, STFT jumps to about 10%, definitely a lean condition. Remaining constant at idle is NOT indicative of a vacuum leak so I'm at a loss as to explain what's going on. Do I have a bad MAP sensor? The P0106 tends to suggest this, but there may be other reasons for the P0106. I'd rather avoid just replacing parts in a process of elimination as that could get quite expensive. So I need to know how to continue my diagnosis. Anyone?

Answer 1

P0106 Manifold absolute pressure (MAP) sensor circuit performance

P0171 Fuel system lean

SFT 3 and LFT 4  Putting in drive it jumps to 25. The idle remains constant?  All this is fine if you are very sure of no vacuum leaks,  When you have a P0106 the ECM see the MAP at a slow response.,   which you do have.  When at idle if the long fuel trim LFT is 4 that great, the short fuel trim should be at a negative number such as -2 or -3 but you have a total of 7, You are lean at idle. So a vacuum leak is not ruled, This engine has a MAF sensor, Do a MAF sensor cleaning , which is usually the main cause for a lean code, The reason is you may have 2 seperate condition which can not relate  as one issue, If there was a vacuum leak, it could  code a MAF perfromance, Because this engine has a MAF and a MAP  the fuel management needs to be in consideration.. A  MAF can set a lean code, but a lean code will not set a MAP code. This is rationality, If it is rational with P0106 and P0171  these 2 code together is a mecanical condition such as a big vacuum leak caused by a PCV valve or brake booster hose. But if it idles great, then its not mechanical. The codes you have are seperate conditions.Do a MAF cleaning first to solve the lean code condition, recheck the fuel trim. both totaling close to 0. retest if P0106 returns by itself replace the MAP.