CEL flashing, three misfire codes

[snowdogb77]

Hello All,
My '98 has been running rough, and I have replaced the following items:
Crank Position Sensor
Cam Position Sensor
IAC
PCV
Coil, Plugs & Wires
Fuel Filter
EGR position sensor
O2 sensors (downstream)
Removed and cleaned MAF

The CEL comes on flashing, and I have the following misfire codes:
P0302 (cylinder 2) P0304 (cylinder 4) P0305 (cylinder 5)

When I start the vehicle and begin pulling plug wires, there seems to be NO SPARK coming from the coil itself. Is this a main computer problem? Any insight would be greatly appreciated!

 

[snowdogb77]

Found the Solution to this problem

It's been awhile! After replacing every sensor under the hood, and countless hours of digging through repair manuals/bulletins, I found an obscure reference to the timing chain cassettes for this particular year engine. It seems that there was a problem with the chain guides, and they had a tendency to wear badly causing a lot of slop in the chains. If the slop got to be too much, it would throw the timing off between the crank and cam sensors, causing misfires across one side of the coil.

After calling around to several locations, I found that having the cassettes replaced would cost ~$3200 bucks to replace. I did a little more research, and found a company called Neco Engine Replacement (on the web, they subcontract out to local shops) that would replace my engine with a factory remanufactured long block for ~$4500. Since my block already had 100K on it, I went for the long block replacement.

So, to make a long story short, if you begin to have multiple cylinder misfires in your 1998 4.0L SOHC, the probability is quite high that the culprit is your timing chain assembly.