p304 code, loss of power etc.

hondafmx1000

hondafmx1000

New member
So my 96 t4r just threw a code this week p304, misfire on cylinder 4. It was fine for a few days then I felt the power loss and rough idle again. I checked the sparkplug and I also changed the coil pack for cylinder 1/4. The CE light is still on but idk it seems like I'm going thru fuel really quickly and the exhaust smells like I'm running rich. Does anybody have exxperience with this problem? Any help would be appreiciated.


96 sr5 4x4 stock 81k

-dula
 
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x2 on new wires. I had the same problem about 2 months after I put new plugs in. Hooked up some new wires, ran like new, and no more CEL.
 
Thanks guys I haven't replaced the wires yet, ill go ahead and do that as well, and ill keep updated the way if anybody else has this problem its a good reference.
 
I just went through that first going with the spark diagnostics. Turned out to be a bad injector in mine.
 
did you replace the injector yourself? if so was it hard to do or no? i feel like im running out of options and it sucks. i just dont have alot of money to drop to fix it. since its my daily driver i need it to get to work, but i guess a bike will do lol.
 
Kust had the same thing happen to mine whle the GF was on a trip up north. After the stealership tried to bullsh*t us about this and that, turned out to be the injector.
 
I did the injector myself but i am very mechanically inclined and have the tools. took just over an hour all three times. I kept rolling the seal and then didnt get it seated properly. There are two bolts holding the fuel rail on, need to alternate a turn at a time to get fuel rail to seat properly. I kept tightening one and then the other and that is why it was leaking and had to redo it.
 
Okay so today I got in the t4r Nd started and ran great... for an hour, then after I ran into the bank real quick and got back to the car , she started sputtering and felt like she was down a cylinder. So my coil pack idea was a fail. I took it back home and had my dad look, of course when he got in it ran fine, he said maybe I got some bad fuel and gave me some marvel mystery oil and I went and filled it up with premium. Do u guys use low grade fuel or run higher grades? I'm hoping maybe if it is an njector the additive will flush the problem out. I don't want to put my lift on hold because I spent all my money fixing her back up lol. Thanks for the feedback guys.

-Dula
 
So today i checked the CE light again because it came back after i replaced the coil pack, and after looking at the scanner for a while we found a place on the scanner which counted misfires, and well i turned the t4r on and then it started counting it was like 85 misfires in 20 seconds, so pretty much looks like it isnt firing. so im gonna get some new cables and a new spark plug and hope its either one of those, but it looks like it could be the injector if its not those. so at least the misfire is still only on one cylinder, im hoping that i can buy just one wire because i dont wanna drop 70 bucks for a whole set. but ill keep updated
 
hondafmx1000 said:
So today i checked the CE light again because it came back after i replaced the coil pack, and after looking at the scanner for a while we found a place on the scanner which counted misfires, and well i turned the t4r on and then it started counting it was like 85 misfires in 20 seconds, so pretty much looks like it isnt firing. so im gonna get some new cables and a new spark plug and hope its either one of those, but it looks like it could be the injector if its not those. so at least the misfire is still only on one cylinder, im hoping that i can buy just one wire because i dont wanna drop 70 bucks for a whole set. but ill keep updated
Click to expand...

I would do a compression test too. If comp is good, and the miss always stays with cyl. #4 even after you swap coil packs, then it's almost always gonna be either the wire, plug, or injector is bad. A full pack (of 3) wires is about $45. Go with NGKs or Densos.

If the comp is really low or dead, then you have bigger issues.
 
So I'm having this issue now too. I know this thread is a little old but i figured I would try searching for stuff rather than create a new post. So I have the P304 showing up, cylinder #4 misfire. Plugs are fine (checked them), replaced the coil pack for 1/4 with a new OE replacement, and put new plug wires on because my old ones had worn through and were shorting to each other. Now it ran fine for the past 3 weeks, and the problem has come back, same code, and I have no idea what to look for. I've checked the wires the best I can while I'm standing in front of the thing, but to trace it requires taking a lot of stuff off and I just haven't had the time. So is there any way to check if its the injector like the thread suggest? and would it work fine for 3 weeks with just normally and suddenly the problem came back.
 
Pikeman said:
I just went through that first going with the spark diagnostics. Turned out to be a bad injector in mine.
Click to expand...

OP I had the same symptoms as you, it was a dead injector for me as well. Rockauto has original made in Japan injectors for $52 a piece last I checked. Make sure to buy an injector seal kit as well, several in fact. They are easy to pinch when you are putting the fuel rail back on.

Replacement isn't too difficult, when I had to replace injector #2 my brother and I had to remove the intake manifold and move the fuel rail out of the way. You can check the resistance across each injector at the terminals, if one is much different than the others, that's probably the one giving you problems.
 
My symptoms were driving down the highway and then a few stutters, a few more, then just a constantly dead cylinder. It would randomly cut back in a few times. Misfire CEL popped up.

If your plugs and wires are good and you've checked the coils, chances are it's the injector. Seems to be a recurring theme with these trucks as they age, this ethanol fuel with all the water it absorbs sure isn't helping.
 
96LTDrus said:
My symptoms were driving down the highway and then a few stutters, a few more, then just a constantly dead cylinder. It would randomly cut back in a few times. Misfire CEL popped up.

If your plugs and wires are good and you've checked the coils, chances are it's the injector. Seems to be a recurring theme with these trucks as they age, this ethanol fuel with all the water it absorbs sure isn't helping.
Click to expand...

yeah i have 257,xxx on the truck with little knowledge if anything was ever replaced so....
 
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