Headache!!! 98/4.6

[98ExpyinIA]

Had a significant miss several months ago. changed plugs all but #7 (unable to remove) and wires. Ran fine. Heard loud hiss like vaccum leak and found pcv valve hose was cracked near pcv valve. splice it back and cleaned a real gunked up pcv valve. Now significant miss again with loss of power under load/uphill, rich fumes smell (burns the eyes), still can't remove #7 plug. Pulled codes; P0304, P0306, P0308, P1506 (that says see P0507), C1226 and P0325.

HELP! I think I'm getting 14 gallons to the mile..... not really but extremely poor mileage....

 

[SkyJumper]

First off with your spark plug that you seem to not be able to get out. You need to make every effort to get it out. It is tight in some areas, but you should be with a little patience be able to get all plugs out and replaced.

the codes mentioned are,

PO304- Cylinder 4 misfire detected

PO306- Cylinder 6 misfire detected

PO308- Cylinder 8 misfire detected

PO506- Idle Control System RPM Low

PO507- Idle Control System RPM High

C1226- Has to do with Chasis, but what I do not know

PO325- Knock Sensor 1 Circuit Malfunction Bank 1 or 1 Sensor

Have you checked your coil packs to see if they are producing properly?

 

[98ExpyinIA]

No I have not, I'm somewhat mechanically inclined, but do not know how to check the coil packs. There are 2, drivers and passenger side, front of motor...

 

[Mikiedoo]

Well,
Im getting around 11 mpg city with my fully functioning , great running expy so Im thinking your mileage isnt bad...lol

Have you washed the engine in any way ? Gotten it wet somehow?
This can cause multiple coil pack issues.

 

[jrjr]

fyi
About 14mpg with my 97 so far.

 

[98ExpyinIA]

No, but it doesn't matter if it gets wet or not... Out still jumps and sputters and backfires, fumes burn the eyes sometimes, I use 1/4 tank of gas in40 miles (extended tank). It sometimes tries to accelerate normal but just gets very erratic
....

 

[wiley84]

I was having some of the same problems with my 07. missing bad going up hill and some times on the flats. I just so happened to be on vacation so there wasn't much option except to go to a dealer and they found 4 and 8 coils packs bad. ran great for about 150 miles then started missing again. took to anther dealer and found #6 coil pack bad, had them change all the plugs seems to be running fine now. if you changed all the pulgs and still missing try changeing coils

 

[98ExpyinIA]

Are 4,6,8 on the same coil pack (I don't have COP's)? Might as well change both since I have 218k on it....

 

[98ExpyinIA]

anything else besides coil packs I should check?

 

[SkyJumper]

I would stick with the coils as I stated earlier. Or you have some wires misrouted after you installed the new plugs.

And to answer your question concerning the spark plug location relative to the coils.