Persistent Undiagnosable Problems with 2013 Tacoma

I have a 2013 Tacoma Prerunner with 155,000 miles, here are my problems. It started when I used a copied key without the transmitter. I tried starting the truck, but the truck wouldn't turn over. I stupidly thought it was the battery so I tried starting it with a portable jumper, maybe even abused the jumper a bit to try and get it started, tried using the original key and it started no problem. However, I didn't put it together that the key was the problem. Next time I tried starting the truck I was having the same problem, ended up changing the battery, spark plugs, and alternator and still wouldn't start, I changed the fuel pump relay and the truck started right away. I drove it for a week before it wouldn’t start again.

I had it towed to the mechanic and they told me the key was bad, however, the original key was also giving them trouble. They replaced the fuel pump resistor and the truck ran for about 2000 miles. While driving on the interstate, for maybe half a second my RPMs dropped but came right back and it drove fine. Later that day I went to start it after parking it and the truck would start but then lose RPMs and die. I cleaned the Mass Air Flow Sensor, which was covered in soot, and it started up no problem. An hour later I went to start it after driving for a few miles and it did the same thing, starts but then dies after about a second. I cleaned the MAF sensor again but no luck. I let it sit overnight and it started the next day.

I drove it to the mechanic and after looking at it for a couple days they said it started every time and they couldn’t figure out the problem I was having. I went to drive it out of the parking lot and it did the same thing. The mechanic looked at it again and said it was losing fuel pressure but couldn't be sure it was the fuel pump. I drove it for a couple days before having the same problem of it starting and then immediately dying. So I changed the fuel pump and after installation I still had the same problem. I got a code this time of P0102(low mass air flow circuit). I bought a whole new sensor but again didn't change a thing.

I then had it towed to a dealership this time, they tried telling me it was all the aftermarket parts, and I had fouled spark plugs from the engine being flooded. They cleaned the plugs, drained the fuel, and cleaned out the lines. It ran for a couple days before the problem came back. This time I was able to smell gas after it started and then died. I had it towed again to the dealership and they are now telling me it is the fuel pump that needs to be replaced because it is not OEM, and it shut off on them($1400).

So first the engine was getting too much gas but now the pump is shutting off. I can't figure out what is wrong with the truck and I don't trust anyone really knows what they’re talking about especially with the dealership trying so hard to sell me parts. I am close to getting rid of the truck since no one can figure out what is wrong with it. Any advice will be greatly appreciated.

Edit 1.
I went ahead and had them replace the fuel pump and it drove for a few days. While driving on the interstate going at about 75 mph the RPMs dropped completely and the truck stalled out. I attempted to start it several times, and it would start but then immediately die.

I had it towed to the dealership again, and after five weeks of being worked on I got the truck back. The dealership told me they opened up a case with Toyota to find out what the issue was(I'm not sure what that entails). They replaced the ECU, fuel pump relay, fuel pump(again), fuel pump suction tube assembly, and replaced potentially damaged wires, they also didn't charge me anything and gave me a loaner this time. After the installation they kept the truck for several days to try and see if the problem persisted, which after assuring the problem was fixed I picked up the truck.

The service advisor said there was nothing I did that could have caused the issue, it was more likely that the parts became faulty over time. I am sharing this in case anyone has a similar issue, so I hope this helps someone else out.

If I continue to have any problems I will update the post for anyone who may be interested.

 

We need to stop throwing parts and do some actual diagnostics or find someone that does, sounds like so far everyone has just been guessing at it.

 

x2

 

easter egging never ends well.

 

Since everyone you mentioned so far seems to think it's centered around the fuel pump something to check would be Pin 8 (Black/Red) of the IB1 connector behind the left kick panel for any burning/discoloration.
Beyond that we need the truck acting up and start checking things with a scan tool and test light.