I have a 99 Ford Ranger 3.0L Fuel Flex. It has a really rough idle and little to no power. Also, it has a hard time running with the air conditioner on. Have changed the coil pack but it really hasn't helped much. Have replaced the plugs several times. It has been having a problem were one of the plugs goes bad after about a month of use.

It gave 7 codes...
P0303
P0304
P0306
P0133
P1401
P0171
P0174

Anyone have any ideas?

I'm not sure about the codes but for the rough idle turn the truck on and take the main vacuum line off the break booster and put automatic transmission fluid through it, a quart is how much I put, then if it shuts itsself off leave it off for about twenty minutes then take the intake tube off and spray can cleaner on the butterfly valve and wipe it off with a good towel then put the intake tube back on and turn it on and rev it up some and it will smoke because of the atf but it should clean everything out and make it run noticably better

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93' ranger, 3.0 5 speed, purple, regular cab long bed, 03' rear bumper, 06' mirrors, 03 mustang seats, 235/75R15 maxxis big horn mud grips, 03' stock rims painted, 2'' leveling pucks, and all new bearings, seals, brakes and 3.73 gears in the rear.

just had a p0303 on my 99 4.0...replaced my plugs and its been good since...champion iridum 3401's..how old are the wire??
your codes p0303-p0304-p0306 are cylinder misfires. the rest maybe caused by the misfires...02 sensor may need tobe replaced-p0133- slow responce bank 1 sensor 1 so the front o2 on cylinder 1 side/ passanger side
p0171/0174 system lean..
p1401 egr back pressure... may need to be cleaned or repaired/replaced

I have a 98 3.0v6. runs great when cold but misses at idle and just above idle whon warmed up. I got some of the codes you did.

i had the same codes i took it to a shop and just as i suspected i had a clogged injector

I bit the bullet and took it to the shop. Two bad injectors, #5 & 6. What a pain in the ass to replace them. Going to replace all 6. Hope this fixes the problem.

Thanks for the help.

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1998 3.0 automatic extra cab.

was grandpaws truck 80,000 mi

stepside with oversize wrangler tires