my engine started missing or something today at a stop light. it only happens every once in awhile and at idle. the engine has also stumbled a few times taking off from a stop. i figure something needs to be cleaned, but im not sure what.
does it happen in drive, or nuetral? what year and miles on your car?
of course the obvious plugs, wires, coil, pvc, clean fule injectors w/
chevron techron. if you've tried all these, consider test at auto zone for
code readout, check EGR, and a few sensors,,, VSS, TSS,,, etc.....
Could be a coil pack failure. These failures are common at 50K+ on the V8 SHO engines, and somewhat less common, but still a problem, on the Duratecs with the same "coil-on-plug" design. They fail from excessive heat, and they can be very difficult to diagnose at first. One of the few tests that will help you out is a "load balance test" that can usually be performed only at the dealership. They will basically find out how much power each cylinder is putting out. The weak one(s) is/are the one(s) that you should try replacing the coil(s) on.
You could also remove each coil pack individually and test it in the following way:
-Inspect the coil and boot for cracks or other damage
-Shake the coil and listen/feel for rattling
-Test the resistance across the coil input terminals and compare to the other coils
It could also be common stuff... vacuum leaks, bad connections, etc. Check the IAB/IAC (Idle Air Bypass/Idle Air Control) which is right on top of the throttle body. Unplug the electrical connection and clean it out. I believe you can clean the IAB/IAC passage itself by removing the "accordion" hose on the intake and spraying TB/Carb cleaner through it while the engine idles.
Had that in the '97 Sable Duratec. It also missed here and there in idle and idling in gear, the RPMs would go south. Cleaned the throttle body with throttle body cleaner, end of problem.
The can of TB cleaner is not expensive at all and the procedure is easy and you can do it yourself. Just keep the butterlfy valve open at all times because if the rpms drop the darned thing can backfire, which could result in a burn. Stupid as I am it happened to me when I was almost over, that's why I'm telling you.
Check your air filter and either clean or replace it, also check the gas filter and replace if needed.
That's like the cheap stuff. If all the above doesn't work then go for the more expensive items as suggested.
You may as well have your engine codes checked to see if there is an error code, sometimes they may not trigger the service engine light on the dash.
I'm getting the samething at idle. It started off a while back, and left for a while, but is back again. Sure feels like spark to me, but I'll try cleaning up the throttle body first. Should be easy enough to do at lunch. Will move into the spark if that does not cure it. Just feels like one or more of the cylinders is not firing from time to time.
I have a 97 Duratec with 89K miles. Runs great otherwise.