We have a 2002 Tacoma that has engine problems that the dealership cannot figure out for the past year.
When starting the engine runs rough and we often get a check engine light/301/302 codes. If you don’t keep your foot on the gas, the engine will die and then not restart for 5 mintutes. After about 10 minutes of running on less than all cylinders, it straightens out.
After a few days, the check engine light will go back off. We have swapped coil/wire from cyl 1 to 5 with no change, run fuel injector cleaner, changed plugs, etc. and kept up with all maintenance.
It is only on starting when cold. Sometimes doesn’t happen for a month, then back again 2-3 times a week.
Any ideas on what else to test without blindly replacing parts “hoping” it will fix it is much appreciated as this is getting expensive for an old truck.
The next thing I would do is swap the #1 & 2 fuel injectors with 2 others. Or maybe just pull the fuel rail and check the actual injector behavior in general.
Also check the fuel pressure regulator - this is done easily enough by checking it vacuum hose for raw fuel - there shouldn’t be any.
Is this only on cold start, only on hot start or either one?
Only on cold start.
We have not kept strict weather records, but wet damp weather seems to trigger more often. And we used to get only code 301, but now getting a bit worse - last time was 5 codes all at once - P0301, P0300, P0301PD, P0302. What does the “PD” mean?