1991 AW4 NP231
I'm having a bad misfire between 2700-4000 rpm while idling and under load. I've been trying to diagnose it for 2 weeks now and have ran out of some ideas. No Check Engine Light. I've searched and used google search for .
Symptoms
-No power during acceleration
-Bucking/misfire during WOT
Parts Replaced
-Bosch O2 sensor
-Aftermarket CPS
-Aftermarket TPS
-ValuCraft Coolant Temp Sensor
-New Cat when smogged 5 months ago
-Autolite Double Platinum Plugs .035 Gap
-Duralast Wire Set
-Fuel filter
-cap and rotor changed 5 months ago
Diagnostics
- MAP sensor Prong B is 1.6v with Key in on position
-Prong B with motor on is .5-.6v
-removed flanged cat to rule out plugged exhaust. Still misfire at idle.
- was told the champion plugs I had before the new Autolites were fouled (white in color)
-sprayed the intake manifold and had a small leak on the TB base gasket but has since been replaced. still misfire.
-Put fuel rail on a gauge and its 40psi idle, 41-43 at WOT with no load. It does fluctuate between 41-43, is this normal?
-found a little oil in the distributor but cleaned it out
Thanks in advance.
I'm having a bad misfire between 2700-4000 rpm while idling and under load. I've been trying to diagnose it for 2 weeks now and have ran out of some ideas. No Check Engine Light. I've searched and used google search for .
Symptoms
-No power during acceleration
-Bucking/misfire during WOT
Parts Replaced
-Bosch O2 sensor
-Aftermarket CPS
-Aftermarket TPS
-ValuCraft Coolant Temp Sensor
-New Cat when smogged 5 months ago
-Autolite Double Platinum Plugs .035 Gap
-Duralast Wire Set
-Fuel filter
-cap and rotor changed 5 months ago
Diagnostics
- MAP sensor Prong B is 1.6v with Key in on position
-Prong B with motor on is .5-.6v
-removed flanged cat to rule out plugged exhaust. Still misfire at idle.
- was told the champion plugs I had before the new Autolites were fouled (white in color)
-sprayed the intake manifold and had a small leak on the TB base gasket but has since been replaced. still misfire.
-Put fuel rail on a gauge and its 40psi idle, 41-43 at WOT with no load. It does fluctuate between 41-43, is this normal?
-found a little oil in the distributor but cleaned it out
Thanks in advance.