Skip the auto shop - Our mechanics make house calls

Q: Truck misfires when the engine warms up - 1995 Chevrolet C3500

asked by on

When I bought this pre-owned truck, it had 145,000 miles on it. The truck has a 454 and a 4L80-E transmission. During a long road trip, it started misfiring. I figured this was caused by low-quality gas but it wasn't as it kept misfiring even when I put quality gas in. I had the fuel filter replaced and the previous owner said the fuel pump is almost new. The truck starts immediately and runs fine for a while. When the engine warms up though, the misfiring occurs. The truck has no trouble developing and cruising at high speed though. The engine has power. The dash isn't showing any lights on either. Temperature gauge is at 175. What kind of repairs do you suggest?

If the heat sensitivity is a good clue, this could well be the ignition control module, which is quite heat sensitive on the big block Chevy’s. Would check fuel pressure (while running) as well to make sure you’re getting enough fuel. Engine temperature seems low, as well as the thermostat may not be staying closed enough to get to design running temperature. A YourMechanic professional can help with the misfiring issue and make all necessary repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Truck misfires when the engine warms up - 1995 Chevrolet C3500

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Transmission lights no gears

Hello. Your BMW 745Li has a shutdown feature which helps to prevent additional damage to other components of the car when there is a problem with the engine and/or transmission. Using the information that you have provided, it sounds like...

Q: misfire

Engine misfires can be caused by a list of problems, but there are a few suspects that occur more than others. The primary culprits are simple – spark or fuel – usually manifesting in spark plugs, plug wires, the coil(s)...

Q: Heater is not warm enough

Hi, thanks for writing in. The temperature of your heater is going to depend on the circulation of the coolant, temperature of the engine, and the associated parts working correctly. The blend door actuators, level of coolant in the system,...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...