Multiple Cylinder Misfire

[vanilla_gorilla312]

I've got a problem with my 1997 hoe. When I accelerate anymore than under normal driving conditions, i.e. passing a slower car, or accelerating onto the freeway, my hoe starts to tremble and sounds like its missing, and the check engine light comes on and starts flashing. I first pulled up the "Too Lean left bank O2 sensor" code, so I changed both left bank O2 sensors (Bosch) and it still did it. This time I got a "Multiple Cylinder Misfire code" so I decided it was time for a tune up anyway. I replaced the Distributor Cap and Rotor (Duralast Gold), Bosch +4 Fusion Sparkplugs, Bosch Sparkplug wires, changed the oil (Royal Purple) and filter (K&N) and replaced the fuel filter. It still does it. Do I need to change the right bank O2 sensors too just to be safe? Any ideas

 

[992door]

run some seafom in your gas. maybe you got some trash in one of your injectors. No i would not change the other ones no point if it is not on that side.

 

[James909]

Also make sure there are no vacuum leaks.

 

[BOSS]

Check all vac hoses, connections, inj harness, spark plugs.

And read JK's 6.0 thread. You'll be pulling the cats out of the exhaust loop to test I bet Just test and test twice, we missed it the first time somehow.

I've got a problem with my 1997 hoe. When I accelerate anymore than under normal driving conditions, i.e. passing a slower car, or accelerating onto the freeway, my hoe starts to tremble and sounds like its missing, and the check engine light comes on and starts flashing. I first pulled up the "Too Lean left bank O2 sensor" code, so I changed both left bank O2 sensors (Bosch) and it still did it. This time I got a "Multiple Cylinder Misfire code" so I decided it was time for a tune up anyway. I replaced the Distributor Cap and Rotor (Duralast Gold), Bosch +4 Fusion Sparkplugs, Bosch Sparkplug wires, changed the oil (Royal Purple) and filter (K&N) and replaced the fuel filter. It still does it. Do I need to change the right bank O2 sensors too just to be safe? Any ideas

Ok ok I'm guilty. I didn't read your entire post....sounds like clogged cats to me. Still, read JK's 6.0 swap thread.

B

 

[JKmotorsports]

There are several things will cause the pcm to set those particular DTCs, but the most common causes for multiple misfire and lean bank DTCs is a fuel delivery issue, leaking intake gasket, or a clogged cat.

 

[99Yukon_Z71]

Run the seafoam like they said, but I bet that if that does not work, you will be replacing the CPI Spider system. It is a fairly common problem in our 1996-2000 trucks. I have done over alot of these!!! Let us know....

 

[knotty]

here is what was wrong with mine .......i replaced 5 out of my 8 injuctors and still ran like crap so i took it back to the shop and found out it was a faulty cap , it has never ran this good since i have owned it !!!! its crazy i just pelaced the cap 1 month prior but i guess now i know that you can buy new parts that are bad only cost me 200 to figure it out but im back on the road ! YAY ME

 

[vanilla_gorilla312]

I have bought a faulty cap once on my 1989 Chevy 1500 pick up. I will try the seafoam first and go from there, cheapest to most expensive of course. Thanks for all the ideas.

 

[hapyspaz]

Yeah, your lean O2 codes are because of the misfire, very often O2 codes pop up and very rarely is the a problem with the O2's.

As 99Yuk stated, you are more than likely looking at a bad fuel pressure regulator. Unfortunately it is mounted inside the upper intake manifold with the "injectors"

Try the seafoam, but this may be where you end up.

 

[vanilla_gorilla312]

well I tried the seafoam but with no improvement in my problem. I am going to look into the fuel regulator and catalytic converters. Thanks for all your help. Will keep you posted on the progress