I have a 1998 Honda accord and the check engine light keeps flashing. I have scanned the car and it says it has a misfire on cyc 4 and 5. I have checked plugs and wires and distributor and they are fine. when the car is running it runs ruff and has a skip to it. you can smell raw fuel at the back of the car where the exhaust is. Could this be a bad valve?

 

When you say the plugs, wires, and distributor are fine, how did you check them? voltage, spark, ohms? A no cost way would be to swap the plugs and wires from 4 and 5 to another two and see if the error moves. If you are smelling fuel, I would think that means a spark issue. When you inspected the spark plugs (I presume you pulled them out) did you notice fuel on them?

I suppose you could have a valve, but is there something else to the story here? DId you have a timing belt issue or something else happened before this?

 

Once check all the spark plugs and then check the vaccum links for any damage and then check for fuel pressure if the fuel pressure is low then try changing the fuel filter and andthe fuel pump check the battery for any problems.thats it

 

a vaccum leak isn't likely to cause a cylinder-specific misfire. if this were a P1399 then maybe. same story for the filter and pump. if the issue is fuel related, the injectors should be checked first.

OP, injectors can be swapped around like the plugs to see if the issue follows. it's more messy and more trouble, but if you rule out spark/ignition it would be worth trying. don't forget to number your plugs and injectors with a sharpie or paint pen to keep track of what back goes where.

compression loss is another possibility. in my experience a burnt valve is most likely. A leak down test would be the proper way to diagnose this one. there are some shade-tree alternatives too.

 

Agreed it could be a vlave, but before you get to what might be a valve issue, I would do all the other swaps first (injectors, spark plugs, wires). that will give you the first clue of whether it's a part you can just swap in for repair or something possibly more serious.

 

Possibly, luckily #4 #5 are at the front of the car, pull off the cam cover, check valve clearance, do a compression/leakdown check and eliminate any possible mechanical issues first.
Since the upper plenum has to come off as well, verify the EGR port is not obstructed or overly sooty.

If there was any recent work done before this problem occurred recheck that work.