98 5.0 Explorer Bank 1 Misfires | Ford Explorer - Ford Ranger Forums - Serious Explorations
  • Register Today It's free!

98 5.0 Explorer Bank 1 Misfires


New Member
October 6, 2008
Reaction score
Hi Everyone,

I have 98, 5.0 Explorer that is misfiring/not firing on bank 1 only. It was running rough so I hooked up my timing light and every cylinder in bank 1 misses firing about every 5-10 revolutions. I changed plugs, wires, MAF (it needed it) and intake gaskets. It won't pass emissions and was throwing a CEL for too rich, too lean bank 1 but I haven't see it since replacing the intake gaskets. I pulled plugs on bank 1 and they where pretty fouled. The missing gets worse when reving up the engine. This seems to be an ignition problem, but I don't know much about computer controlled engines, because it just plain misses firing. Any thoughts? :mad:


I have a few
While taring my engine down-I noticed the harmonic balancer had "shifted" position-
it is a 3 part design, a pulley-balancer, timing gear retainer and a "strobe wheel" for the crank position sensor. They three parts are wedged together with a rubber sleeve inside the tube-
kind of hard to explain, but when the crank sensor flags were at TDC, the engine actually wasn't. It was off by a few degrees. Save this one for last-as it is hard to check

Also-you might check out the camshaft position sensor. It it is dirty, or "flaking out" it may trigger mis-timed fuel injector pulses.

you might want to check the fuel pressure. Check the fuel pressure regulator vacuum line for gasoline smell . If there is gas-or gassy smell in the regulator line it may be bad
Also run a can of "seafoam" thru the engine. Beware the seafoam will foul the spark plugs with the blown out gunk

after this-you might look to see if there is an injector ( or 2) leaking through-causing the fouling out

You might also have a coil pack which is "carbon tracking" an arc across it-maybe try swapping them for each other. Try this one first.