Why is my car constantly getting a check engine light?

Question

Let me start off by saying that this car starting having problems in May. Back then, I got a code P0171 (system too lean - bank 1) and found it to be the fuel/air ratio sensor. The PCV and MAF sensor were also changed, but I feel they were unnecessary. Anyway, about 30 days later, the check engine light comes again. This time I get misfire codes and it was found to be a leaking fuel injector. That cleared the check engine light for about 120 miles of driving. But once I went high speed on the freeway, the check engine light came back. It showed random misfire codes. Spark plugs and wires were changed out. But spark plugs in cylinder 2, 4, and 6 had carbon on them. The spark plugs on 1, 3, and 5 look great. It's too soon to tell if these new spark plugs will get carbon on them again. But for now, I am now getting only code P0171. My mechanic says it is the O2 sensor since the fuel/air ratio sensor has already been changed. I don't know if I will get misfires again. I don't want to drive it at high speed on the freeway just yet. This car is a 1998 Toyota Camry XLE with a V6 engine. Any suggestions?

Update:

The car has a light hesitation of power now, but not much. When the P0300 misfire codes were there, the check engine light would blink and have much more hesitation of power along with shaking under the hood. I got this car back in 2001 with 46,000 miles on it; now it has just over 127,600. Never had the oxygen senor replaced in all this time.

Ryan · Accepted Answer

pretty sure ive got the exact answer your looking for. to start off i had a 96 sunfire, had the exact same codes as you, system too lean (bank 1) and random multiple missfire. i replaced the o2 sensor, the throttle position sensor, new plugs, fuel filter, air filter crank sensor,and coil pack, yea its alot, about 700 dollars counting the fuel pump. it turns out my cars fuel pump had low fuel pressure. most cars have a schrader valve on the fuel rail (where the injectors are) it looks like a valve stem on a tire. take it to a mechanic and have him do a fuel pressure test, usually they are really cheap. as for your plugs, i just changed some in a 98 chevy lumina,  the plugs on the back of the motor where covered in carbon, not sure if what cylinders they where. i found out later that the guy had been replacing the front and not the back because they where too hard too get too. also every time i would put a sensor or part on the car it would make it run better it seemed like for a day or two then mess up again. are you having any symptoms? or just a light?

? · Answer

"cylinder four" manner the pc is detecting a mis-fire on cylinder four. Founded in your description of the way it's performing, i'd bet it can be surely misfiring on extra cylinders then simply four but the laptop shouldn't be detecting the others for some purpose. While you say you changed the "boots", do you mean the coil packs? The first thing i might assess is that the coil packs are all working appropriately for every spark plug. There may be customarily a method to assess them and your neighborhood auto ingredients maybe able to inform you how (in many instances they have got that kind of diagnostic data on file). Clogged injectors might be the problem...But i'm going to say that possibility is less probably on this one. Subsequent factor to investigate is compression...Low compression on a number of cly would motive that (bad rings or burnt valves). Other possibilities is a foul pc mind, melted wiring going to the coil packs or injectors, or potentially a bad O2 sensor. The reason the A/C prompted the engine to die is the extra load of the compressor was once an excessive amount of for the engine even as misfiring.

Chuckles · Answer

It is getting old and telling you that it is time to think of newer wheels. Once a Toyota starts to get cranky, they get expensive.

Trending News

Why is my car constantly getting a check engine light?

3 Answers