First, I don't know if this matters but the truck has always had slight rough idle. Took it back to dealer 4 times and the last time they said Ford expert told them its normal for 3.0L V6.
Here's the problem. Runs fine at start-up, will start misfiring after warmed up. MIL codes say "random misfire" "misfire on cyl 1" "misfire on cyl 2" "misfire on cyl 3". Have cleaned MAF, cleaned idle control valve, replaced plugs--plug wires--coil pack--fuel filter. Compression checks fine. Cleaned fuel injectors. Swapped O2 sensors from bank 1 with bank 2, problem says on bank 1. Fuel pressure checks fine. TPS tests fine. Runs fine at higher rpm. If I power brake at stops things are good, but if I let it go below 1500 rpm it will start misfiring almost every time. Then have to rev engine in neutral to regain power. Cylinders will kick back in and run fine. Or when this happens I can turn engine off, restart and runs fine till the next time I let it get below 1500 rpm. This is diving me nuts, any suggestions. Help, Ed
Here's the problem. Runs fine at start-up, will start misfiring after warmed up. MIL codes say "random misfire" "misfire on cyl 1" "misfire on cyl 2" "misfire on cyl 3". Have cleaned MAF, cleaned idle control valve, replaced plugs--plug wires--coil pack--fuel filter. Compression checks fine. Cleaned fuel injectors. Swapped O2 sensors from bank 1 with bank 2, problem says on bank 1. Fuel pressure checks fine. TPS tests fine. Runs fine at higher rpm. If I power brake at stops things are good, but if I let it go below 1500 rpm it will start misfiring almost every time. Then have to rev engine in neutral to regain power. Cylinders will kick back in and run fine. Or when this happens I can turn engine off, restart and runs fine till the next time I let it get below 1500 rpm. This is diving me nuts, any suggestions. Help, Ed
Oct 14, 2009 at 9:58 AM