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'89 chev S-10 Tahoe


spike's Avatar
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04-26-01, 09:41 PM   #1  
spike
Hello everyone,

I have a pickup that has had an intermittent problem for years and I wonder if anyone has an idea. The vehicle is a 1989 chev S10 Tahoe 4WD with a 4.3L V6 fuel injected engine, automatic transmission. Sometimes, especially in cooler weather after it has been sitting for a couple of days, it will cough, sputter, and backfire when you load the engine even a little bit. Typical scenario: Monday morning-Starts ok, head out on highway to go to work. After about 7 - 8 miles at 70 mph, starts to cough and sputter, must be careful not to step on gas very much and probably will have to shift into lower range to keep going. Sometimes it is very bad, other times just a little bad. If I have to stop, a very good chance of stalling and very difficult to start when in this condition. But, If I keep driving, after about 50 - 60 miles it will clear up. Or if I let it set for a couple of hours after getting to work, it is usually fine for the rest of the week. Have tried changing the fuel filter 2 or 3 times, changed spark plugs twice, used injector cleaner, tried gasline antifreeze. None of these things seemed to help. No error codes in diagnostics last time I checked. The cold weather connection doesn't always hold either, I have often had it happen in warm weather too although less often. Sorry about the long post. Any ideas? Thanks

 
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04-27-01, 12:18 AM   #2  
knuckles
This may sound like a stupid question, but when was the last time the spark plug wires, distributor cap & rotor were changed?

I've seen HUNDREDS of 4.3L and 5.0L engines with corroded distributor cap terminals and bad spark plug wires. The above usually causes anything from a dead misfire to an intermittent shut down. Check the cap/rotor/wires & let us know what you find.

 
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04-27-01, 05:47 AM   #3  
Joe_F
No question is too stupid. I recall a neighbor's Cadillac that had Cadillac ENGINEERS come by to look at why it stalled, sputtered and hesitated. They changed everything...the problem? A rock solid clogged fuel filter.

Also, have you check the fuel pressure? Any vacuum leaks? How's the condition of the rest of the engine?

 
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04-28-01, 11:22 AM   #4  
spike
Hello Knuckles, Joe F.

Well Knuckles, it appears that you may have hit the nail on the head. Or at least one nail. I pulled the distributor cap today and it didn't look good. Lots of a white powdery substance, interior spark terminals both on the cap and rotor pretty eroded. Found a piece floating around inside that appeared to be a part of center coil terminal that should extend down close to center of rotor, broken off flush with interior of cap. A certain amount of rust also. I guess I'll have to round up some parts and not take distributors for granted anymore! Joe, to answer your questions, I don't have a gauge to measure fuel pressure, there don't seem to be vacuum leaks although there are so many lines on a modern engine that one could easily escape me. Engine has been running pretty good except for occasional problem as I described. From past experience I think that it will take months after repairing this distributor problem to know for sure if that cured it. Thanks guys.

 
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04-28-01, 02:41 PM   #5  
spike
Correction-

I think I broke of the loose piece when I was horsing the old cap off. Well I now have a new cap and rotor, and will probably get some wires later. Now time will tell.

 
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04-30-01, 05:28 PM   #6  
That sounds like your Fuel injectors. I had the same problem
weather conditions and all. After awhile it won't start at all. good luck

 
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04-30-01, 07:54 PM   #7  
spike
Hello Sonardog,

Did you end up having to replace the injectors then?

 
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05-01-01, 06:06 PM   #8  
Yes and It's starting again. This was over a year ago. I hate this vehicle.

 
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05-02-01, 10:01 AM   #9  
Joe_F
You'd be making an expensive error (as some trucks have 2 fuel injectors in the throttle body) if you were wrong, even if you went with rebuilt units for this.

You can't condemn the injectors or even the fuel system as being bad until you've done a fuel pressure check to eliminate/substantiate it as a cause!!

 
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09-16-01, 04:42 AM   #10  
spike
Update,

After replacing distributor cap and rotor, vehicle has been running without problem all summer. Coming into fall now, we'll see I guess.

 
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03-23-02, 09:04 AM   #11  
spike
Final Update

Engine has been running well all winter. Cap and rotor cured the problem.

Thanks guys!

Spike

 
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