code p0303 misfire cyl 3

[modelageek]

This has been an on going issue. 3 months ago I got a bad bucking that made the truck almost non drivable. At the same time it threw a P0303 code (misfire cyl 3). I change the fuel filter, the FF was really bad. The I added a a large bottle of techron to the tank. I drove the truck and within 5 miles it was back to almost normal.just I then drove the truck for a few months with a hesitation. Today the hesitation was a little worse so I checked the codes. I got a pending p0303.

I changed the plugs (bosch double platinum) and wires( Bosch) about 10k miles ago. I installed a new IACV about a month ago. I cleaned the maf and have a good airfilter. The hesitation comes and goes. What would cause this that. There is no signs of a head gasket problem. the truck does not use any oil. Any feedback would be appreciated. Oh.......and I checked fuel preasure 2 months ago. It was 62(keor) and dropped to 54 in 6 min(koeo) ...thx

 

[SMTGREG]

Check the compression on all cyl.When the plugs are out do the electrodes look the same? REPLACE the plugs with MOTORCRAFT plugs!!!! Swap the injectors #3 and # 2. When the injectors are out look at the fuel tips they should look the same. Clear the code and drive until the code comes back. If the code moves to a diff cyl you have found the bad part. If the code stays in #3 It could be a sticking or burnt valve, bad cam lobe, follower or lifter. Swapping parts from different cylinders will help find the cause at a minimal cost.

 

[modelageek]

I was going to do a compression test on the passenger side and replace those plugs with autolites/motorcraft. I have to pull the intake manifild off to change the injectors correct?

 

[modelageek]

I think I solved it......i rented a compression tester and bought 4 new autolite double platinum plugs from AZ.......I removed the plugs on the passenger side to do a compression test. I could not get the tester to work.....so i just installed the new Autolites on the passenger side....... The miss appears to be gone..... the plugs don't look horrible but there is a lot of black tar looking stuff on the flat part of the plug and in the hollow area. The Bosch plugs have only been in there about 5 months and 9k miles......... I did seafoam the truck twice through the break booster and it smoked a lot ........i am wondering if the seafoam messed up the plugs or maybe bosch plugs just suck....... I am going to replace the drivers side and hopefully it will run even better.......

 

[modelageek]

SOLVED.....DONT USE BOSCH PLUGS.......

9k miles ago I went to get plugs all AZ had was Bosch I new i shouldn't get them bet i wanted to get the job done..........I am not sure if the seafoam treatment did the damage or not......but the porcelin looking part of the plug had small holes in 2 of them. I replace with Autolite and used autolite wires also..seems to be working fine...........what a waste of myu time and money if I had just bought motorcraft or autolite the first time........the good news is I am getting better at changing the plugs. I did not take the intake off and did the plugs and wires including cleanup in 1 hour and 35 minutes......

 

[97ranger xlt]

somewhere i read you need to change plugs after doing a seafoam treatment
...on the other hand others have said repeatedly only use motorcraft/autolite plugs in the 2.3
glad you got it solved