Engine misfiring. Spark plugs, ignition coils, spark plug wires, shitty gas??
My 2001 Toyota Echo (180,000 miles) started to
sputter and shake when I started it to head home
from the grocery store. (It was shortly after I had
filled it up with gas in an unfamiliar station with
high detergent in their gas.) I was scared to keep
driving it, but I got it to the parking lot of a
mechanic a few miles away, along the way my
check engine light came on. I got a diagnosis from
the mechanic there, and he said after running 3-4
codes that he thought it was 2 out of 4 of my
ignition coils misfiring, and he wanted to replace
those, as well as all my spark plugs. The parts are
old and never been replaced because the car never
had any trouble. The spark plugs and ignition coils
are a really easy fix as far as I can tell, so I'd like to
do the work myself. My only concern is how
reliable his diagnosis could be. I know its entirely
possible to have bad wires or a host of other
problems that mimic my car's problem. I'm worried
that I will replace these parts and my car might still
not run properly. How can I tell what the real
problem is? He also said that it wasn't misfiring
while he was running it. Is it necessary to have to
replace all of my spark plugs when I replace the
ignition coils? Trying save money if I can. Thank
you for the advice ahead of time.