| Author |
Message |
    
Joshua Smith (98hoo)
| | Posted on Monday, December 30, 2002 - 01:35 pm: | 
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I have been having this problem for THREE YEARS!!!! Usually when I am travelling at 55 mph or above, the truck will begin to vibrate, and then go away. Been getting progressively worse. The check engine light comes on, so I had the codes read. The #8 cylinder is misfiring, and there was a problem in the catalytic converter on that side. So far I have replaced plugs, wires, speed sensor, had the valves checked, had the injectors cleaned, verified spark, and compression tested within a couple pounds of the #6 cylinder. Does anyone have any other advice on how to diagnose the problem, or better yet how to fix it. I am ready to light the thing on fire!!! |
Robert Sublett (Rubisco98)
| | Posted on Monday, December 30, 2002 - 01:38 pm: |
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Just started getting the hesitation the other day and my codes read out (misfire on #8, and an O2 sensor or catalytic fault I cannot remember) I'm planning on replacing the plug wires this weekend. Sorry I don't have any advice but at least you know someone has a similar problem. Peace.. RS |
Joshua Smith (98hoo)
| | Posted on Monday, December 30, 2002 - 02:41 pm: |
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Please let me know if you come up with a solution Robert, it is driving me nuts. |
Mike B.
| | Posted on Monday, December 30, 2002 - 07:28 pm: |
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Plug your voltage meter in to your system and watch see what is happening electrically when the problem occurs. The problem you describe can happen when the voltage drops too low.
You can hard wire your voltage regulator to your cigarette lighter and drive around with it hooked up. The Bass Pro Shops sell a digital model that plugs directly into the cigarette lighter and it's very accurate (within 1/10th volt). In case you are interested, the part number is part (38-600-818-00). It's called a Vector Voltmeter and sells for $14.99. (And no, I don't work for Vector or Bass Pro shops!)
Thanks,
Mike B. |
Joshua Smith (98hoo)
| | Posted on Tuesday, December 31, 2002 - 07:58 am: |
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What is an acceptable voltage? |
Ron
| | Posted on Tuesday, December 31, 2002 - 01:27 pm: |
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5 and 8 are the most common sticking valves. VSS shows up as odd cylinder misfires.
Ron |
Paul Long
| | Posted on Tuesday, December 31, 2002 - 07:40 pm: |
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Joshua, does the miss at highway speed do it occasionally or is it predictable that it will continue it constantly? My 99 DII will misfire on 7, sometimes 8 ONLY at highway speed when backing off the throttle gradually. You notice a vehicle running slower in front of you, can't get into the passing lane right away and back off. That sets the code and feels like rough road or a tire is out of balance. Romp on it to richen it up, goes away. It will decell OK downhill with no miss. I have OBD-2 on a laptop and it records while you drive to replay and watch everything monitored later. Only comes up with "lean bank one and two" when the misfire happens. Nothing else out of the ordinary. Like you I've tried all the normal stuff. I believe mine is a case of needing the parts crash cart to try this and that till you hit it. Could be the ECU itself leaning it out too much under just the right conditions. Mine started doing it at around 50,000 mi. and it has taken me 17,000 more to not figure it out yet. I'm ready to start switching injectors to see if the problem moves to another cylinder. I average 20 mpg and other than the occasional miss, runs strong, very smooth idle, no other issues. Dealer says valve guides too tight. I say if that were the case it should happen at higher revs when the valves can't close quick enough, or on long hard accelleration up hill when valves are at their hottest. Under load mine shows no sign of a problem until throttle is backed off. Sound similar to the conditions that set your code? Paul |
Joshua Smith (98hoo)
| | Posted on Thursday, January 02, 2003 - 10:10 am: |
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Sounds exactly like what you just described Paul, except I only get 10 miles to the gallon. The most recent diagnosis I heard dealt with optical sensors behind the flywheel being dirty. Any experience with this? I am hopefully meeting with another experienced mechanic this weekend to get his opinion. He says it could be a cat, or the computer just being too sensitive. I will give an update ASAP. Still looking for suggestions though.
Thanks. |
Mike B.
| | Posted on Thursday, January 02, 2003 - 05:27 pm: |
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Joshua:
On a D1 with GEMS (96-99), 13.4 volts is break even. Anything lower and you are draining the battery, anything higher and you are charging the battery.
I haven't metered a 94 or 95, but it might be about 1/2 volt lower since it still has the distributor.
Thanks,
Mike B. |
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