diesel engine throttle response

[jdalrymple1953]

I own a 1994 K3500 Chevrolet pickup with a 6.5 diesel engine. When it is hot outside the throttle is sometimes slow to respond, or sometimes will drop out as though I removed my foot from the pedal. It has great power once it does accelerate. Has anyone out there had a similar experience and found the trouble. If so please let me know what to look for. I have purchased a couple of manuals to no avail.

[chriscampbell]

It could be the PMD, its the little black box on the drivers side of your injection pump. Its the driver for the pump, they are bad about going out on the stanadyne pumps on these trucks. They range in symptoms from stall, miss, no start, hesitation, prob more.. You might want to check the warranty on the truck, diesel injection pumps are covered for 10 years or 120,000 miles. hope this helps!!

[jdalrymple1953]

Thanks for your reply to my post. Do you know how the PMD can be tested and what the approximate cost of replacement is?

[chriscampbell]

Its hard to diagnose the PMD unless you catch it in the act with a scan tool, I still don't know if it will show anything or not. If it ever stalls(like you shut the key off) or misses while driving down the road its almost always the PMD. I'm thinking the cost for the PMD is between $250 to $300. If you do replace it be sure to swap the resistor from the old PMD to the new PMD, its in the connector cavity. Hope this helps!