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Q: The motor starts lurching and my speedometer and tachometer start pegging out, the truck keeps running though

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As I'm driving along the truck will start lurching and the instruments will start fluctuating, I can continue driving and the problem will stop but it will do it again, sometimes it smells like the exhaust is leaking. I replaced the battery a month ago and there was a starting issue with it, one of the wires to the positive terminal, the one with the fuse link, was sketchy. I would have to jiggle it to get it to start, I replaced the fuse in the link. What's going on with this thing.

My car has 311518 miles.
My car has a standard transmission.

A: Hi there. It would appear, there is a poor ...

Hi there. It would appear, there is a poor electrical connection or wiring issue still present. This would account for the engine lurching (a loss of power or ground to the fuel or ignition system) and erratic speedometer and tachometer. It may be power supply issue and/or poor ground related issue. Taking another look at the replaced fusible link(s), may resolve the problem. It could be, a charging system related concern. A failed alternator diode(s) could create unusual electrical problems. The exhaust smell could be, an electrical smell. I recommend having your vehicle's engine starts lurching and erratic speedometer and tachometer be diagnosed and repaired by a certified technician, such as one from YourMechanic.

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