Posted: 1/7/2004 10:09:38 AM EDT
| Hey...need some thoughts...1993 Chevy K1500 305...While going uphill (rather steep) the truck will buck and shudder...seems to run well on level ground...Changed the plug wires yesterday (were original)...and changed the plugs 6 months ago...one thing I do notice now is that I feel a pulsation through the #1 plug when I put my finger on the boot of the wire...don't know if this was the case with the old wires...don't know if the pulsation is related to the miss going uphill or not...any ideas on what to try...Thanks guy's... |
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checked the fuel filter? i had a toyota celica do something similar years ago. Turned out that the fuel filter was starving the engine under a load but normal driving wasn't much of a problem. not a mechanic and never claimed to be one. just passing on a possibility. |
| Since you describe the problem as happening under load, I believe your problem is ignition and not fuel. When you drive under load, such as an uphill/acceleration condition, more voltage is required to ignite the air/fuel mixture. Once higher voltage is put through the ignition system components, it becomes easier for the higher voltage to find it's way to ground through carbon tracks or cracked spark plug insulators. If the spark shunts to ground before it jumps the gap of the spark plug, the engine will misfire. Take a look at the distributor cap and rotor. Look for carbon tracking inside the cap. This was a very popular problem with Chevys from the early 90's. If the cap and rotor are ok, you either have a bad wire or a cracked spark plug insulator. |
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Quoted: I dont really understand what you mean by pulsating. What did the plugs look like when they came out 6 mos ago, and when did this start? You can feel a tapping through the wire...only on one wire all others are ok...almost like you can feel the electic pulsation through the wire... Started about 2 weeks ago...plugs looked fine when replaced... |
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I'd say filter also or fuel pump is starting to go bad. Pulse in the wire is nothing. Electric going through it around 50,000 volts. Look at your wires at night with no other light on to see if they are throwing sparks over to other metal next to them. Check or change distributor cap also. very small cracks are hard to see but will kill your power. Let us know what worked. COZ |
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You can use a water bottle and spray fine mist of water under the hood to aggrivate an arching wire also. I would change fuel filter first then I would start looking at ignition. What is your tach doing during this bucking? If your tach is freaking out it's SURELY a ignition issue. |
| have someone bring the RPMs up and remove a plug wire from the distributor cap one at a time. listen for a difference in the sound of the motor. if you find one that doesn't make a difference the that is the wire or plug that is shot. use a wire removal tool, don't use your hand, plug wires can give you a nasty shock |