Connect a scan tool, look for short- and long-term fuel trims, MAP voltage, TPS voltage, Coolant sensor signal, and ALL THE REST of the sensor information.
How about pending codes?
Blunt the sharp tips of eight small nails. Apply a little dielectric silicone grease, and slide 'em between the wire and the boot at the distributor cap, until the nail touches the metal end of the plug wires. DON'T puncture the insulation. That way, when you're done there's no damage to the system.
Ground the lead of a test light--or just use a grounded jumper wire--to ground the spark to individual cylinders.
A scan tool makes that easy.
Worse in closed-loop, somewhat better in open-loop?When warming up the engine runs smoother but has a noticeable roughness in it, once at operating temp it idles rough, even worse in gear with the ac running, it almost seems like a miss at times only at idle!
How do you know?The engine currently has no SES codes and starts up easily!
How about pending codes?
Removing plug wires with the engine running creates an open-circuit. That drives the coil secondary voltage sky-high, making life very difficult on the secondary-side insulation. Don't do that. Ground the spark instead to kill an individual cylinder.Wires are delphi-packard all of them ohmed out good, when removed one at a time they all caused the same change in idle.
Blunt the sharp tips of eight small nails. Apply a little dielectric silicone grease, and slide 'em between the wire and the boot at the distributor cap, until the nail touches the metal end of the plug wires. DON'T puncture the insulation. That way, when you're done there's no damage to the system.
Ground the lead of a test light--or just use a grounded jumper wire--to ground the spark to individual cylinders.
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How do you know that the sensors are good? How do you know that the sensor wire harness is good?cap and rotor are new
icm and pickup coil have been replaced
coil has been replaced
Coolant temperature sensor test out good
i swapped the map sensor with a known good one
replaced the 02 sensor with an ac delco 02 sensor i pulled the iacv and cleaned it
A scan tool makes that easy.
What is the fuel pressure at the throttle body? Doesn't matter what the pressure is before the filter, if the filter is plugged.fuel pump was replaced with a delphi unit 3 years ago, currently has 11psi of pressure before the filter.
I'd expect poor vacuum from an engine that is running rough.i checked the vacuum of the engine, it set on 18 but would drop as it would rough idle/miss