Engine Performance problem
2002 Toyota Camry 4 cyl Two Wheel Drive Automatic 56000 miles
The Problem: I drive a 2002 Toyota Camry 4-cylinder that I bought used in November. It had low mileage (56,000) and had seemed like the previous owner had taken good care of it. I will provide the extensive detail below of the problems I have been having, but at the moment, the car misfires often and hard when it is absolutely cold then proceeds to get better (almost to the point of perfect) as the engine warms up. I have been to two different dealerships at least five times for help with this, and no one can figure it out.
History: After owning it for a few months, I started having trouble with the engine misfiring (and during that time I also moved from Houston to Nashville). I took it to the closest dealership (Dealership #1) which couldn't figure out what was wrong with it because they said all of the read outs were where they should be. Eventually they blamed the problem on bad gas and dropped the tank to clean out the water and debris.
The problem improved but it continued to occur, so after a month of running fuel system cleaners through every tank, I took it back in to Dealership #1. This time they now said I needed to replace all four fuel injectors and the mass air flow sensor for $1500. That seemed ridiculous to me as I know that fuel injectors don't go out very often especially not all four on a car with only 64,000 miles or so.
After looking around online and in the Mechanics Files, I called around for prices and chose to take it to another dealership across town (Dealership #2) that gave me the second cheapest price for that work and was rated very highly by its customers. Their first recommendation was to change the coil pack in the third cylinder because the error code followed that coil as they moved it. I warned them that despite what the computer might be saying right now, I have had multiple misfires constantly. They said this would fix it, and they recommended a throttle body and top engine clean to remove the carbon deposits from misfiring so often.
Dealership #2 did the cleaning on a Friday while they ordered the part, and replaced the coil on Tuesday. The day I picked it up and started it, I could tell that the problem was not solved. I drove it for a day with no improvement and dropped it back off again. While the cleaning seemed to help it run smoother, the coil pack made no noticeable difference.
That Thursday I was trying to leave town to drive to Texas for my best friend's wedding, so Dealership #2 looked at it all day often with three mechanics including their master technician giving it a lot of time. After spending all day with it and looking at the timing among other things they had no great epiphany. They recommended running some of their stronger fuel injector cleaner through it as I drove to Texas. I did that and it seemed like the car was running much better, but again, because the car was warm on the entire drive it was hard to tell for sure.
Once I got back to Nashville, I started it up the next morning to head to work. The engine started and revved up to about 1500 RPMs and then down to about 800 RPMs which is its typical range at idle. I put the car into reverse and held the brake for a few seconds, and the RPMs lowered to 500-600 which caused the car to misfire often and hard. I let the engine sit there like that hoping that maybe something was getting pushed through the gas line and it would even out. As best I can tell, the only thing that will even it out is the engine warming up. On the third day of this happening and experimenting with it, the engine actually misfired so much that it died.
I took the car back to Dealership #2 yesterday (Friday) though unfortunately I could not drop it off and let it sit over night. They let the car sit until after lunch and looked at it as cold as they could get it. This time they said new codes had popped up for the mass air flow sensor, so they changed that out and sent me on my way.
This morning I woke up, crossed my fingers and started my car. And it is still having the same problem. I don't know a lot about cars, but I do know a little bit about science. At this point my guess would be that when cold the fuel pressure is lowered for some reason and is not getting enough gasoline to the engine, or perhaps there is a seal or connection somewhere that is wearing out which is shrinking as it cools and then expanding to fill whatever hole it is in as it warms up.
At this point, I have spent just under $1000 on the problem (which is close to an entire two-week paycheck for me), and have replaced an ignition coil, the mass air flow sensor, cleaned water and debris out of the gas tank, pushed two heavy-duty fuel injector cleaners through, and cleaned the throttle body and top of the engine with no great improvement. No one seems to be able to figure out why the car is now running better when it is warm but even worse when it is cold.