How old are your plugs?

When was the last time you cleaned your throttle body?

Good luck,
Sam

 

"nstalled a new MAF sensor and air filter - still no remedy.|
Can you post the MAF error code?
If changing MAF sensor didn't clear MAF error code then could be a MAF circuit/ wiring problem.

 

The code was P0101 and I haven't changed the plugs since I bought the car. (Bought it used with 52000 miles) What about the possibility of a vacuum leak or crack in the air intake hose? That might set off the MAF sensor....

 

"The code was P0101"
If changing MAF didn't clear the P0101 then check circuit/wiring.
Can you post the MAF reading in g/s?
BBBind.com has schematic of MAF wiring.

 

Still having the same problems

I'm not sure how to get the MAF sensor reading.... I just replaced the plugs and still have the same problems: low idle, sluggish acceleration from a stop, lousy gas mileage. I have yet to check the air intake hose.

 

mike, get a code scanner, tell us what set and pending codes you have and your long and short term fuel trims, and maf grams / second in closed loop at idle and 2500 rpm, so we can start to get a handle on this.
google elm327 bluetooth and 'torque' and shoot us the information when you get it.
tony

 

^^^

Ltft and stft can give you a very good ideal on the basics of the engine health from either vacuum or iginition issues.


Does the issue seem to change as the car is cold started then warm up to normal spec? Idle is just low or does it have a miss to it?

 

I mis-reported the OBD code at first. Had the system rechecked today and the code is actually P0171 System Too Lean (Bank 1). Will look into getting the ELM327. Hoping to find one locally but they only seem available by mail order. Low idle comes and goes whether it's cold or at running temperature. Haven't noticed a miss. And, on occasion, it seems to run/accelerate just fine. But still has a hard time accelerating at freeway speed. Plus engine seems to "hold back"/hesitate when accelerating at freeway speed. I guess that would be a symptom of it running lean... (?)

 

"What about the possibility of a vacuum leak or crack in the air intake hose? That might set off the MAF sensor.."

Vacuum leak can be the cause of the P0171.
Lots of info out there on checking for leaks such as spritzing soapy water around intake/manifold watching for bubbles.

 

I couldn't agree more since you recently modified the intake, that would be the most likely scenario. A loose clamp will cause MAF/ECU confusion and force the car into LIMP mode.

I'm having doubts about the Fuel Pump as the 2GR-FE is Direct Injection (DI) and the pump provides consistent Fuel Rail PSI. I would have checked PSI at the engine side schrader? port [if there even is one]. Not sure what the proper PSI is, but I'm sure it's well over 100. I know some DI engines are at a crazy 2500 PSI...

 

If you got a code for P0171 then your running pretty lean, at least IIRC 25+

Could be a really big vacuum leak, bad o2 sensors, or maybe a bad MAF.

 

So after replacing MAF sensor, PCV valve, new plugs, air filter, cleaned the throttle body, checked hoses for vacuum leaks, air intake hose cracks it seems that the problem was the upstream O2 sensor. I disconnected the battery before starting the replacement so the CEL would go off and ECM would reset to base state. The car starts easier and on-road acceleration is back to normal. I drove it on city streets and highway for about 15 minutes to get engine stats back into the ECM. Only glitch during that time was that car is still hesitant on acceleration from a dead stop. I'm hoping that will change during the next drive cycle or two.

(As an aside, I got the sensor through WalMart. Had it shipped to a store in a couple of days, no shipping charge. Total cost was about $140. Rockauto.com has the lowest price at $105 I think, but, due to money issues, I had to charge it through WalMart. The "retail" price seems to be about $170 for it. The downstream sensor only costs about $40.)

I bought the OEM Denso O2 sensor instead of an "off brand". The fact sheet for the Denso sensor does recommend it be replaced after 100k miles. It sure would be nice if Toyota had a note to do that in it's maintenance schedule. I guess I was about 65k miles too late to do this.... Hope this thread helps someone out there that has these same problems...

 

Hmm. Wow. No CEL for the O2 sensors though, right? This is very good information. You only had the P0171 code?

 

Thanks for getting back.

 

I had same problem. I found a few reasons:
dead ABS module
bad speed sensor
bad MAF
dirty throttle
last one bad pedal sensor.

Last 3 problems don't show any codes.

 

Well, I replied too soon that I found the solution. The car does run better since the new O2 sensor but the sluggish acceleration from a dead stop and highway acceleration are still a problem. I failed to mention that a few months ago, in order to save a few cents, I put in E85 gas a few times. (But have been running regular unleaded for a couple of months lately.) All these symptoms began to pop up after a ran the E85 in the car.
My registration is due so I tried to get past the inspection by having the P0171 code cleared and going straight to have it inspected. The code came on during inspection and it failed inspection. They said that I needed to have the throttle body replaced. I once again tried to clean the throttle body hoping that might help but it didn't. I had my wife hold down the gas pedal with the key turned ON but car not running so I could clean down inside the TB. I noticed that the butterfly valve opened quite slowly with a jerky motion. I'm not so sure that this is normal. I figured it would go wide open as quickly as she pressed the pedal. Anyone know if this is "normal" operation for the butterfly valve? Does it indicate that replacing the TB is what I need to do?
(I also pulled out the fuel pump to check the "filter" and inspect the gas in the tank. All looked fine and the car does start fairly quickly so I assume the pump is still good. I've seen posts saying that E85 gas can mess up a fuel system even though the pump stickers state that it's fine for cars made after 2001 or Flex Fuel cars.)

 

Yes, now nothing but the P0171 code. Without the A/C running the car is fairly normal. The only "problem" seems to be acceleration when I'm going about 45 MPH and punching the accelerator (very hesitant, jerky response). I've had the battery checked, and along with that, the alternator. The battery is OK but it the tester indicates that the alternator is going bad (voltage regulator failed and diode test failed). Using a voltmeter there is a charge going back to the battery but it's only 13.2 volts when the engine is running. I haven't disconnected the battery for the time necessary for the ECU to reset since I last cleaned the throttle body, so I'm wondering if I should do that and see if it makes a difference. This is getting really frustrating since nothing seems to help much....

 

since you know the alt is bad, how about replacing that and see if that fixes the problem?

as for resetting/losing the ecu information, no reason to do that as it will reset itself once the condition that caused the code(s) is fixed and you've driven it a few miles. so get a code scanner, learn how to use it, read out your 6 monitor states when they're ready and you have no faults set or pending and your long and short term fuel trims added together are less than 10%, let us know if the problem still persists after all this. (don't forget to verify 14.2vdc at the battery engine idling.)

tony

 

Hi, MikeB, I have a 07 Camry with 152255 miles, and I have also received a code P0171. Have taken my Camry to Toyota twice. The first time I took my Camry to Toyota they replaced Air fuel ratio sensor, and fuel injection and throttle body cleaning and PCV valve. Picked up my car and after less than 100 miles the check engine light is on again.The second time Toyota repaired my Camry they updated some software. Now my Camry check engine light is on again. Please advise I would think Toyota mechanics could repair this type of problem easily; no so.

 

Agree, sounds like a misdiagnosis.
If original P0171 wasn't fixed by the installation of parts/cleaning then they own you a redo.
No other codes other than P0171?

 

Code P0171

Hi, cj1, Yes I believe they you are right they misdiagnosed my Camry two times already. I take my car in Monday morning because the check engine light is on again. Toyota did not charge me the Second time I took the car in to be checked. thanks

 

Changed out the fuel filter and pump today. Cleared the code and took it for a drive. It started right away like it used to do. Acceleration is back like it should be, both from a stop and at highway speed. I soooo hope that the problem is gone now. And it seems like many people on this forum have the same P0171 code popping up. They try replacing all the sensors with no remedy. Seems that the fuel filter and pump motor is the solution.... BTW I got both at www.carpartswholesale.com for less than $30... If this was the cure then this thread is done. Otherwise, I'll be back.

 

I had a similar problem with my Toyota Camry 2007 with 180,000 miles on the clock. I tried several mechanics without success. Then I took it upon myself to try to figure it out. All the while, the car sounded like it wasn’t “breathing “. So I took out the bank one-oxygen sensor and “vrooom”!!! I drove it out for a while while and in my excitement burned the paint on the hood! But I didn’t mind that a whole lot. I hadn’t been to work for two weeks. So I ordered the catalytic converter from EBay for $100 and fixed it myself. I wasn’t going to pay a mechanic for that. I hope this helps someone in the same predicament I found myself in.