The specs: 1990 XJ, Renix 4.0, 30k miles, manual.
The issue: While driving and NOT heavily accelerating, just cruising along maintaining speed, I've got a wicked misfire/stumble. Seems to do it at any RPM as long as there isn't alot of load on the motor. At Full throttle or even 3/4 throttle while accelerating it pulls fine. It idles fine. It accelerates fine if I'm really accelerating. If i'm just lightly accelerating or maintaing speed is when it stumbles/misfires.
What I know is good/replaced/etc:
O2 sensor is good/new
coil good/new
TPS tested perfect
CPS good/new
plugs good/new NGKs gapped properly
wires/cap/rotor new
fuel pump good/new
fuel filter good/new
fuel pressure reg good/new (pressure tests perfect to spec)
Vaccuum tests good at 16hg/in
Compression tests good at 135 +/- 1 psi all the way across (done with motor cold for about 5-7 cranks)
IAC cleaned, appears to be good
EGR moves smoothly with vac
ECU grounds look good (I also put a few extra 4guage grounds between the block, the frame and the battery)
Another issue JUST started happening while I was doing some diag early today, but it appears my coolant likes to come pissing out of my coolant bottle now with a little pressure(still old style cooling system). It is still a rusty-ish water color, doesn't look like oil or gas in it, smells like coolant. The exhaust has no hints of water/coolant. That combined with the consistant compression numbers makes me think its something other than a headgasket. Also, this could just be cause it was a hot day and I was dicking with it without really driving it around.
SOOOOO...?
Anything I should recheck? or Perhaps I'm not thinking to check?
hasta
The issue: While driving and NOT heavily accelerating, just cruising along maintaining speed, I've got a wicked misfire/stumble. Seems to do it at any RPM as long as there isn't alot of load on the motor. At Full throttle or even 3/4 throttle while accelerating it pulls fine. It idles fine. It accelerates fine if I'm really accelerating. If i'm just lightly accelerating or maintaing speed is when it stumbles/misfires.
What I know is good/replaced/etc:
O2 sensor is good/new
coil good/new
TPS tested perfect
CPS good/new
plugs good/new NGKs gapped properly
wires/cap/rotor new
fuel pump good/new
fuel filter good/new
fuel pressure reg good/new (pressure tests perfect to spec)
Vaccuum tests good at 16hg/in
Compression tests good at 135 +/- 1 psi all the way across (done with motor cold for about 5-7 cranks)
IAC cleaned, appears to be good
EGR moves smoothly with vac
ECU grounds look good (I also put a few extra 4guage grounds between the block, the frame and the battery)
Another issue JUST started happening while I was doing some diag early today, but it appears my coolant likes to come pissing out of my coolant bottle now with a little pressure(still old style cooling system). It is still a rusty-ish water color, doesn't look like oil or gas in it, smells like coolant. The exhaust has no hints of water/coolant. That combined with the consistant compression numbers makes me think its something other than a headgasket. Also, this could just be cause it was a hot day and I was dicking with it without really driving it around.
SOOOOO...?
Anything I should recheck? or Perhaps I'm not thinking to check?
hasta