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Ted Ritter
Ted Ritter, Toyota Master Tech
Category: Toyota
Satisfied Customers: 4307
Experience:  Toyota Master Tech, ASE Certified
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2001 Corolla, hesitates on acceleration, hard to start, CE

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2001 Corolla, hesitates on acceleration, hard to start, CE light has been on for over a yr but it has 138,000 miles, a friend says the trouble code says "running lean". I changed the fuel pump about one year ago because of the same problem which was not nearly as bad at that time. New fuel pump did not really make it any better and it gradually got worse. Fuel pressure regulator was not replaced when pump was changed. In the past two months, I have had it on computers at 3 different shops (two were free, one was about $100). All 3 said it was missing on cylinders one and four and running a little lean. The first one said I needed a new coil pack. I got one $120 and tried it on each cylinder. It was no better. Second shop said it was missing and “maybe running lean”. Third shop said the same & they changed the plugs yesterday. It is now much harder to start but supposedly not missing on cyl one & four now. They asked me to bring it back next week when they have time to put it on the rack to listen to fuel pump. They think my car's computer may not turn on the fuel pump consistently, but I always hear it when I turn on the key and for a few seconds & also after I turn off the motor. Third shop had me get catalytic converter checked at a specialty shop. It is working fine. When car was about one yr old, it began to hesitate or stumble on acceleration about once every month or two but only when I first backed out of driveway in the morning and shifted from reverse to first gear. I could overcome it if I patted the accelerator up & down a little. When it hesitates, it will speed up a little each time I let off the gas when I pat it up and down.
Submitted: 8 years ago.
Category: Toyota
Expert:  Ted Ritter replied 8 years ago.
Is the check engine light on now and if so I need to know what the diagnostic trouble codes are.
Customer: replied 8 years ago.
Yes, ce light has been on for months. Unfortunately, I do not know what the trouble codes are. I was told that one code said it was missing on cylinders 1 & 4 (???) and that it was running lean. I am sorry that I did not get the code numbers---- I thought that shop was going to solve the problem, so I did not ask for the exact numbers. (I am wiser now.) I may be able to get someone to pull the codes for me tomorrow and send them to you if that is needed. I am sorry if this is making this harder.
Expert:  Ted Ritter replied 8 years ago.
Not a problem, if there is an autozone or other autoparts chain store in your area call and see if they can get the codes for you, most of them will do it at no charge, I just need the code numbers to give me a direction to go in.
Customer: replied 8 years ago.
I got the codes today from AutoZone. They are PO171, P0300, and P0301.

P0171= "Fuel trim bank one condition: a rich or lean condition on one engine bank only.      P0300= Cylinder misfire detected-- Random cylinders. The powertrain control module monitors the crankshaft speed and has detected a misfire condition.
     P0301 = Cylinder misfire detected-- cylinder number 1.   

My wife is the primary driver of this car, and it is getting harder and harder to start (especially when motor is hot). I have been puzzled by this for quite some time. Thank you very, very much for your help.
Expert:  Ted Ritter replied 8 years ago.
Thank you, XXXXX XXXXX codes are causing the PO171 lean code so this needs to be addressed first, there is a misfire on number one cylinder only, you should check the basics first which would mean doing a compression test to verify if the cylinder compression is the same as the rest of the cylinders, you have already tried a new coil on the #1 cylinder so if the compression is good I would start to suspect a possible injector failure, an injector that is not working correctly will also cause a lean code and misfire. If you want to go through the trouble try switching injectors to see if the misfire moves to a different cylinder, if so you have found the problem and all the injectors should be replaced. You may also want to consider having the coolant temp sensor checked, a scantool connected to the computer can read the coolant temp and the tech should be able to tell if it's bad or not by looking at the freeze frame data or current data.
Customer: replied 8 years ago.
Thanks, XXXXX XXXXX try these steps tomorrow and get back with you if that is OK with you. I have never used this "Just Answer" service before. I am very happpy with your answers and will clicK the "ACCEPT" button soon so you can get your money. I am afraid/uncertain though that if I click "Accept" right now, I may not be able to get back with you before this problem is finally resolved (in case I need to try any other suggestions from you before ending this episode). I will get back with you ASAP to let you know how it goes tomorrow.
Expert:  Ted Ritter replied 8 years ago.
Yes, please let me know the outcome, I may have some additional input for you.
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