P0701 P0171 P0174 on my 06 FREESTYLE 3.0. Check Engine & Wrench appears. It doesn't pop up instantly but after an hr of driving, engine revs but acceleration is minimal. I sit back let car warm up. I changed MAP SENSOR, next up is the Transmission fluid and filter plus 02 sensors. I've had this car a month. Until last week these same codes came up. I only drive from home to work. On to the Major Deagon, to the FDR, over 59th street bridge. Usually a lot of traffic due to interstates and bridges. By the time I get by 59th my car jumps upto 3k rpm with that type of rpm I expect to spill my coffee. But It accelerates as if I lightly tap the gas. What do I do? I don't want to invest my money when I can save up for something new. But if its light work I can do it myself. Can you also let me know where to check for a vacuum leak?

SOURCE: Jaguar x type 2004 2.5 petrol V6, 38500 miles, codes P0171, P0174

Have exactly the same issue on 04 jag x type 2.5. So far have replaced fuel filter, air filter k&n, plugs ngk. Codes cleared, same issue. Seems to appear when air temp is cold and eng is warm.
Am replacing upstream O2 sensors and cleaning MAF next. Will keep you posted if it clears up. Did you ever find the cause?

SOURCE: 2000 Pontiac Montana... Turn on... Good. Drive

No, O2 Sensor would make your van to be none fuel efficient at least or won't change anything if it's the O2 Sensor or Bank2 ( It mean's the 2nd one, the 2nd one is a dummy.. it just read what's going out from the catalytic converter and tell's the computer if there's a change since the reading of the first 02, so the computer see if or not the catalytic do his job ) For your Jerking and Jumping problem.. those Gm Van has alot of transmission problem and maybe your transmission on a way to take vacancy or it is just missing oil ! Check Oil first, for that do that when the Motor is Cold, Start you Van Leave it in "Park" Position, Pull the Dipstick of your transmission ( Should be the Red one ) clean the end of it with a Rag and put it back, pull it a gain and check if the oil is in the reading, if not add the missing oil while the motor turn's, and recheck it until it's full ! Otherwise if the dipstick show's Full, Here's a tip's go to your local autopart's supplier or store that sell's car product such oil's, coolant ect.. ! Buy a Bottle of : Lucas Transmission Fix, Remove the Transmission Plug, and remove about the half of the oil ( Not the Whole amount of oil, only the half it's important ! ) and put the plug back well tighten, pull the dipstick and add oil from the dipstick tube with your bottle add about the half of the bottle, start your van, check the oil level if it still missing some oil add the amount it require to be full ( While Motor is Turning ) ! Important do not Overfull the transmission ! This Should Work or not, if not.. I would say you need to Replace your Transmission, What I told you is about 15minutes of your time and a couple of dollar ! Best thing is to bring your van to a Transmission Shop they will tell you the problem !

Testimonial: "Thanks for the honesty, I appreciate it. I just returned from Afghanistan and I have NO CLUE how I am going to pay for all this! thanks again!"

SOURCE: 2002 tacoma 3.4 Rev/Acceleration problem. My

See if you can get one of those shops to "reflash" the prom in your ECM.