Will a faulty RPM relay cause my car to hesitate on power?

[coreydmc]

Hey Guys,

Will a faulty RPM relay cause my car to hesitate on power? Sometimes my car runs smooth and has power, and sometimes it hesitates and lacks power. Kind of like the ignition is missing.

[David T]

Hey Guys,

Will a faulty RPM relay cause my car to hesitate on power? Sometimes my car runs smooth and has power, and sometimes it hesitates and lacks power. Kind of like the ignition is missing.

Typically no. Sounds like an ignition problem or a bad pick-up hose. Do you notice it more on a full tank or when it is less than 1/2 ? If the level of fuel seems to affect when it happens get inside the tank and see what is going on.
David Teitelbaum

[coreydmc]

I dont drive car enough to determine if it reacts differently on fuel in tank. It is hit or miss. Sometimes Ill just start car to pull it out of garage lacks power and is not smooth. If i floor the gas petal is misses real bad. Than the next day it will be totally fine. What is the pick up hose to check?

[David T]

I dont drive car enough to determine if it reacts differently on fuel in tank. It is hit or miss. Sometimes Ill just start car to pull it out of garage lacks power and is not smooth. If i floor the gas petal is misses real bad. Than the next day it will be totally fine. What is the pick up hose to check?

The curvy hose in the fuel tank from the pump to the baffle. Could be dirt or water in the fuel tank too. That is the first place I would look.
David Teitelbaum

[dustybarn]

My RPM relay packed up and the result was that the car completely failed to start. It's hard to imagine an intermittent miss being caused by the RPM relay.

When your car misses, does the tach bounce wildly? That would indicate a problem in the low-tension side of the ignition system.

I had some truly bizarre intermittent spark problems that turned out to be a bad ignition coil.

[dmc6960]

Its a strech, but possible. If the timer circuit in the RPM relay has gone bad, it could be switching on/off rapidly, causing a fuel pressure loss, causing the hesitation. Another possibility could be a poor solder joint in it.

However most hesitation problems are not RPM relay related.