Last post on Aug 14, 2011 at 8:57 AM
You are in the Isuzu Trooper
What is this discussion about?
Isuzu Trooper, Isuzu Trooper II, Electrical, Engine, Exhaust, SUV
#1 of 38 Engine Misfire-OBD Code P0300
Feb 26, 2007 (8:28 am)
I am trying to fix a problem with a '01 Trooper Limited 4WD. The vehicle has 75,000 miles and started to sound rather rough. My wife had the vehicle checked at a shop and was told the EGR valve was bad. I replaced the part as well as a new set of plugs, reset the OBD codes and the car runs a lot better. I am still getting a P0300 code (multilple engine misfire) and the check engine light blinks only when the car is moving. It does not blink when the car is not moving even if the same RPM level is reached. What is causing this misfire?
#2 of 38 Re: Engine Misfire-OBD Code P0300 [krowe]
Feb 26, 2007 (7:11 pm)
When changing the EGR valve make sure to clean out the carbon buildup inside. The original EGR valve on some 01's is known to go bad. The replacement EGR valve is an improved design and should not need replacing again. Both the original and replacement versions are GM parts.
The other known occasionally >60K miles failing part on the 01 Trooper 3.5L engine is the intake manifold gaskets. These are thick composite insulating gaskets, and they can sometimes crack allowing air into the engine. Air input into the engine at a gasket leak bypasses the air filter and engine computer monitoring. This can cause damage from dirt sucked in and poor engine performance because the computer cannot adjust the fuel mix properly to account for the extra air. The replacement gaskets are supposed to also be better than original so the problem will not happen again.
#3 of 38 Re: Engine Misfire-OBD Code P0300 [boxtrooper]
Mar 10, 2007 (5:01 pm)
I've been having the same stalling issues. How much does it cost to have intake manifold gaskets replaced?
#4 of 38 Re: Engine Misfire-OBD Code P0300 [laparka55]
Mar 10, 2007 (8:25 pm)
I don't remember the cost, but the labor was a lot and the gaskets are complicated since they are a thermal barrier so they were not inexpensive either. I had mine done here: http://www.creechimport.com 919-872-1999
#5 of 38 95 Trooper 3.2 SOHC Misfire and black smoke
Mar 17, 2007 (6:25 pm)
Alright I've searched the history and dug as far back as I can to find an answer with no luck! My Trooper has 173K on it, timing belt done at 120K and regular service done always. I was driving for a while, maybe 2 months, with an intermittent check engine light. It would only come on while driving around 50-60 mph then when it would come down to idle speed it would go off. Then one day it started misfiring and bellowing black smoke!!! I had an oil change , fuel and air filter done and she ran fine, FOR A WHILE!!! Then all the sudden it's back the bogging, the smoke. I've replaced plug wires, new Bosch platinum plus 2 spark plugs and new O2 sensor(it was black as were the plugs) and it still is missing???
Any ideas what to check next?
#6 of 38 Re: 95 Trooper 3.2 SOHC Misfire and black smoke [marknroll]
Mar 18, 2007 (12:50 pm)
Black smoke means it is not burning the fuel completely, maybe loss of spark or too much fuel. Maybe the plugs are all firing, but the computer is sending too much fuel.
Is the loss of power extreme when it smokes? That might favor the not firing scenario.
Paison I think, had a failed catalytic converter slowing down the air flow and that caused power problems.
#7 of 38 Re: 95 Trooper 3.2 SOHC Misfire and black smoke [marknroll]
Mar 18, 2007 (12:53 pm)
Hi, did you check the ECM for codes when this started? I would hazard an EGR valve/module issue. Good luck.
#8 of 38 Re: 95 Trooper 3.2 SOHC Misfire and black smoke [marknroll]
Feb 13, 2008 (3:59 pm)
My 92 trooper has the same problem. Have you found a solution?
#9 of 38 engine misfire
Feb 16, 2008 (2:44 pm)
I've had an ongoing problem with the engine having a intermittant misfire, i have cleaned the egr valve and tube, replaced 2 O2 sensors, replaced spark plugs, replaced 1 coil pack, and all tube and valve cover gaskets, but my problem persists. I'm now noticing a rusty oily material in the spark plug tubes. It appears as though the oil and water conbined and evaporated in the tube. I was thinking head gasket, but it seems to me the gasket should not be involve in the spark plug tube, so now i am at a loss. the codes read misfire # 4 cylinder and i replaced that spark plug. Any suggestion would be a good suggestion at this point
#10 of 38 Re: engine misfire [mdenman1]
Feb 16, 2008 (4:15 pm)
What engine are you having this problem with? Generally, I have only heard of antifreeze in the spark plug tubes when the head is cracked. It does happen but pretty rare. More likely the spark plug wire tube seals are letting moisture in. How about spark plug wires.....how old and what condition are they? They may look OK, but age and use can cause their conductance to deteriorate.
HTH One guys opinion.