Mechanics

ROUGH IDILING

1997 Isuzu Hombre

Engine Performance problem
1997 Isuzu Hombre 4 cyl Manual 198000 miles

Today I noticed my truck began to idle roughly. The engine runs roughly only at idle. The engine does not seem rough while I drive. When at idle it feels like the whole truck is rocking.
We are thinking there is a valve problem. Are we correct? If so. Would we need to have them changed? Or adjusted?
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Hanks782
August 7, 2009.



Ok, here are the code defs.

P0172 System too Rich (Bank 1)

P0302 Cylinder 2 Misfire Detected

P1380 EBTCM DTC Detected-Rough Data Unusable.

So, with the #2 cylinder misfiring I would suggest swapping one plug wire for another and if the misfire moves to the cylinder you swapped with then I would say you have a bad wire and would change wires again. You could also check with the parts store if you have the receipt and see if they have a warrantee.

And if that wire is bad that can be causing the code P0172.

I will need to check on the code P1380 because that reffers to the Transmission Control Module and they are usually only used on Automatic trannies.

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Obxautomedic
Aug 21, 2009.
Ok, is the truck 4 wheel drive? If so I believe it is referring to the Transfer Case Control Module. Which would indicate that it is possibly bad.

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Obxautomedic
Aug 21, 2009.
Hubby said the truck is a rear wheel drive not a 4 wheel drive.

Also he wanted to know if the type of plugs he used would make a difference. This time instead of the regular Bosch Platinum he used the Bosch Platimnum Plus 4 (the ones with the 4 prongs) He was told they worked better but after he changed to them we are having these issues.

He said when he gets home he will go ahead and just change the wires and see if it runs better or normally. Wires are not too expensive.

I told him all this trouble means he needs to get me a nice little automatic vehicle. I am getting sick of his manual. HA HA

Tiny
Hanks782
Aug 21, 2009.
Well, Honestly I don't like or recommend them. I haven't had any good experiences with them.

And yes it is possible the plugs are the cause. I always recommend using OE (Original Equipment) or an OE Equivalent Design.

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Obxautomedic
Aug 21, 2009.
Ok Since the last problem with the truck we have changed all the spark plugs and such. There is a new fuel pump.
Ok the fuel is burning too rich. I am thinking we need to change the oxygen sensor and really hoping it is not the injectors. I had remembered one of the codes was P0172 (System Adaptive fuel too rich). My husband has been driving the truck and not me. Since we started having problems I stopped driving it. He came home 3 days ago complaining about the truck not wanting to go after stopping.
He said he has to pump the gas or push the pedal to the floor to get it to go from a stop. Once it is running it is fine. I called a local repair shop to get a price on cleaning the injectors and I never did get a price. All I received was down talk. I guess he assumed since I was a woman I was stupid. Lets just say I am not going to him to fix anything.
I want to know if we should change the oxygen sensor since the fuel is rich. I do not want the truck to get worse. We would like to get it all done this Friday when we get paid. Also if it is the Oxygen Sensor. How many are there? I know it is located at the catalytic converter. Are there two? I believe it calls for the unheated ones. The engine is a 2.2 L SFI 4 cyl. Please help! I am trying to keep this truck alive for at least one more year. Lol

Tiny
Hanks782
Jan 4, 2010.
/Ok, there are at least 2 O2 Sensors one in the Exhaust Manifold at the engine then one by the Cat some models also have one behind or after the cat.

As far as changing it and fixing the problem it may or may not, here some info on running rich.

Because the sensor reacts to oxygen in the exhaust and not fuel, any engine problem that allows unburned air to pass through the cylinders will also trick an O2 sensor into reading lean. A misfiring spark plug or a leaky exhaust valve - even a leak in the exhaust manifold gasket - may allow enough air into the exhaust to screw up the sensor readings. It won't damage the sensor, but it will create a rich running condition that hurts emissions and fuel economy.

So, I would also check for vacuum leaks, and if the misfire is still present in the #2 cylinder then need to find cause.

Obxautomedic
Jan 4, 2010.
Would any of this be what is causing the acceleration problem. We did find one vacuum leak and changed that line. We have not found any others. Since we noticed this problem we have noticed a considerable drop in gas mileage too. We used to get 400 miles to a take and not we seem to have lost at least 100 miles per tank.

Tiny
Hanks782
Jan 4, 2010.
The biggest one that would cause the lack of acceleration is the misfire. If it is still there then need to find cause.

So, if still have misfire need to check Injector and Injector Harness.

Here is more info on the P0302 code - Cylinder #2 Misfire.

A code P0302 may mean that one or more of the following has happened: Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer
Possible SolutionsIf there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.E. Spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.K.A. Coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Here is more info on the P0172 code - Rich condition Bank 1.

A code P0172 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of " oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
There could be a vacuum leak.
There could be a fuel pressure or delivery problem
Possible SolutionsPossible solutions include: Inspect all vacuum and PCV hoses, replace if necessary
Cleanthe MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect fuel lines for cracks, leaks, or pinches
Check the fuel pressure at the fuel rail
Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

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Obxautomedic
Jan 7, 2010.
Ok, well think I have found the problem. Here is the Isuzu code def.

P1380 ABS Rough Road Data Unusable

And from what I have read and found on this code the most likely cause is your PCM. It describes pretty much all the problems you have describe.

I will email you the info I found.

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Obxautomedic
Jan 7, 2010.
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