Hi from Rome, Italy where I converted my 1999 Jeep Wrangler 4.0L in a LPG powered to pass emission restrictions here and run everyday as a daily driver in city centre.
I decided to make this post cause I can't really figured out the problem after many attemps.
Symptoms are some little random misfire ad idle (maybe higher rpms too but not noticeable?) with no codes, no check engine light, no misfire detected via OBDII both in gasoline or in lpg fueled mode.
- Tried 2 sets of spark plugs wires (5k ohms and 3.3k which are in FSM ranges of resistance)
- Tried NGK ZFR5N V-power with a 0.035 gap (0.9mm).
- Tried again old Bosch FQR8LEU2 nickel I founded on the Jeep with both 0.9 or 0.7 (lpg reccomended gap)
- Tried new coil
- Tried few PCM reset with couple cicles to operating temperatures and driving for a bit
- Tried new rotors and distr cap
- Also had new exhaust header & gasket months ago, no vacuum leaks, and TB is super cleaned (sensors too)
No hesitation when revving and the Jeep starts up immediately everytime. Has new battery too.
Idle is perfect but I can feel those misfire via shift knob, steering wheel or under my butt. Also from the exhaust you can hear them.
I know it's not a big problem but when I bought her I didn't have these very little misfire randomly and I have the Bosch FRQ9LEU2 installed..
Problems started not immediately after spark plugs change but a month later.
Suggestions?
I decided to make this post cause I can't really figured out the problem after many attemps.
Symptoms are some little random misfire ad idle (maybe higher rpms too but not noticeable?) with no codes, no check engine light, no misfire detected via OBDII both in gasoline or in lpg fueled mode.
- Tried 2 sets of spark plugs wires (5k ohms and 3.3k which are in FSM ranges of resistance)
- Tried NGK ZFR5N V-power with a 0.035 gap (0.9mm).
- Tried again old Bosch FQR8LEU2 nickel I founded on the Jeep with both 0.9 or 0.7 (lpg reccomended gap)
- Tried new coil
- Tried few PCM reset with couple cicles to operating temperatures and driving for a bit
- Tried new rotors and distr cap
- Also had new exhaust header & gasket months ago, no vacuum leaks, and TB is super cleaned (sensors too)
No hesitation when revving and the Jeep starts up immediately everytime. Has new battery too.
Idle is perfect but I can feel those misfire via shift knob, steering wheel or under my butt. Also from the exhaust you can hear them.
I know it's not a big problem but when I bought her I didn't have these very little misfire randomly and I have the Bosch FRQ9LEU2 installed..
Problems started not immediately after spark plugs change but a month later.
Suggestions?
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