First you have to find out if it's all cylinders that are misfiring or only
one. If it's all cylinders, start by checking the fuel system. If it's one
cylinder, check that cylinder for spark, if no spark fix problem. Check
cylinder for fuel, maybe as simple as it was for me, run car for a second or
two, pull plug and smell for gas. If no fuel check injector, if okay, check
wires to injector. One should be constant 12V while key in run, the other
pulses to ground while engine cranking or running. If no 12V, check wires,
if no ground pulse then check wires. All wires okay, check computer.
As some may remember, I just went through this with my Monte. Turned out to
be a corroded lead for one of the injector drivers in the PCM. But I easily
connected my car to the laptop, found that cylinder number 5 was misfiring.
Somewhat ignore my previous post.
Check fuel system for correct pressure or contaminated fuel. Check ignition
system for proper output. ALLData says it has to be something that effects
the whole engine, so - fuel supply system, air supply system and electrical
supply system, check them all.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.