Hello to All,

I did some research on my problems on the forum here with no luck....
so here goes...

2002 I-35 140k mi....all stock.

past year or so I have been replacing the coils as they fail....done 3 coils so far...Thank GOD # 3 coil is still going....Lol...anyways, got a misfire on #4 cyl.. & it has been running rough for a lil' while.

Replaced #4 coil with new...no better.
replaced #4 spark plug with properly gapped bosh platinum whatever factory plug...no better..

drove it around.... and then got misfire #4 code & multiple cyl misfire code...

car has been in family since new & has always had proper maintenance..

can anyone help me?
Thanks in advance...
Sam

 

oh yea....where is the dang fuel filter even located at??....Lol....

 

I'd check the injector in that cylinder before the fuel filter.

The fuel filter is with the pump in the tank IIRC.

 

thx...I looked for a fuel port under the hood & found none....

Is there a place where I can connect a fuel pressure gauge?

Sam

 

Fuel pressure affects all cylinders so I would look more into spark troubleshooting. Also, Bosch paltinums? OEM is NGK platinums or you can use NGK coppers for shorter service life.

 

sounds more like spark or possibly compression you should be able to kinda rent a compression tester from an automotive store. All you do is pull the number 4 plug and unplug your fuel pump and screw the compression tester into the plug hole and crank the engine. Idk the compression specs but they should be accessible online. also if you have ever done the valve cover gaskets or the intake plenum gasket the wiring that runs along the passenger side of the engine could get messed up because you gotta move it and it gets stiff. so you can also check to the wiring up to the #4 cylinder. Is there any other codes? Possibly and evap or emissions code?

 

so, everything i check is ok
finally take car to tech & he says two upstream cats are clogged. "I can clean em out for 1.5 hours labor"
got car back & ran great..then after 10-20 miles begins to run rough again...
can anyone enlighten me on the cat set up on this car?
thanks..

 

(forgive me, if my question sounds a little naive, but i'm a beginner with these cars)

Question(s)

1. How did you determine that it was a "Coil Issue?"
2. and then narrow it down the fuel filter issue?

 

well I received the for code for #4 misfire...so thats where I started.... & I have also been having coil failure on other cyls...in the past year or so..replaced 3 so far.,,tun got multi cyl misfire code

poor fuel pressure in a efi car can cause all kinds of problems...

 

Just today I messed with the #4 connector to the coil & maybe there is the where the problem be. one of the 'lil connectors looks a little suspect... It can move out of the way when you put it together if you are not careful....makes contact but not a positive one...so, I plugged it together & ran it around & made sure I started & stopped the engine like 3-4 times still ses light & when I get home....1 more start & no SES light! huh? IDK.....
car ran good....

 

I can imaging those plugs in the Back of the Motor are a pain in the **** to get to...(chit)

 

#4 Code....ok...Doesn't make sense to me.

For Example, i at P01800 code on mine which indicated a VIAS sensor error.

Did you take it to an Auto Parts Store to get that #4 code ?