Rough Idle No CEL Code (1 Viewer)

[jltemlock]

Hi Team:

I'm kind of a newb to working on rigs, so hoping for some guidance from the experts on what I should check on my '93 FZJ80. I'm experiencing a rough idle and rough engine under load. It also feels like I'm down a bit of power, but I can swear by that claim. I'm not throwing any CEL codes, so I'm not really sure where to continue investigations.

Thus far, I've replaced some old hoses, changed spark plugs and spark wires, checked the Idle Air Controller, Throttle Position Sensor, vacuum pressure in the intake manifold, changed air filter, checked the EGR modulator (haven't removed the EGR valve as that guy's a beast), and checked impedance for EGR VSV and fuel pressure VSV. Tomorrow I'll start checking through the fuel system and maybe do a cylinder compression test. But, the lack of CEL codes is really throwing me off and I'm just shooting in the dark at this point.

Any expert thoughts on anything else to check is mud appreciated

 

[ppc]

When was the last time spark plugs, wires, distributor cap and rotor changed? Wires will have a date code but also should be checked for resistance and condition.

 

[jltemlock]

Oops. I need to add to the list of things already completed- changed spark plugs, replaced spark wires, checked distributor and rotor (seemed fine)