my '99 es300 with 114,000 started stuttering horribly and my gas went down to getting around 330 miles per tank to 268. I had replaced the read o2 with a denso when the check engine light came on months ago. took it to the shop and paid to have it tested for leaks. he said it was most likely the MAF. I replaced that last week with a denso i bought from advanced auto parts. after driving it for 12 miles, i was convinced i had fixed the problem aside from the check engine light still being on. now it's even worse with the stuttering and is draining fuel like no body's business. It was completely full and ive driven 80 miles and it's at a half a tank already. took it back to the shop and they want to charge me to check all the circuits that are coming up- P0171, P0100, P110, P1135, and P1155. I was supposed to drive this car from Houston to New Mexico to MOVE two weeks ago, and I can't get it to work well enough to drive it safely!! I'm a girl in need of advice ASAP please!! HELP!! thanks!!

 

330 miles per tank is amazing. You must have really good gasoline in TX
Those codes put the car in fail-safe (a.k.a. "limp") mode. It runs rough and won't upshift.

• P0100 is Mass Air Flow Circuit Malfunction.
• P0110 is intake air temp circuit malfunction. This component is inside the MAF

Are you sure you put the MAF in correctly?

 

zoealexand,

You should post this in the ES 1-4th gen forum. Maybe a mod will move this thread.

 

Check the part number on the MAF to confirm it is actually the correct one. Also, it is possible that you have a bad MAF even though you bought it new. Did it look new in the box?

So you changed the rear A/F sensor? What part number did you use? Who installed it?

Buy an OBD2 bluetooth reader if you have an android phone, or a wifi reader for iphone. Torque app for android will let you see the CEL codes and also the output of most of the sensors and fuel trims so you can really see what is going on in your engine.