Q: Engine takes to long to warm up I've replaced thermostat already and it misses horrible till it warms up its a 4.9 engine

asked by on November 21, 2016

My truck runs very poorly in the morning then runs better when warmed up until I shut it off and restart it starts missing again until it runs a little then runs better don't wanna idle in the morning

My car has 1730000 miles.
My car has an automatic transmission.

Fan Clutch Replacement $120.68 - $585.60 Get a Quote
Engine is misfiring Inspection $79.99 - $99.99 Get a Quote

This engine uses a cooling fan clutch that controls the fan speeds on demand when the engine radiator starts to get hot if increases air flow to cool the engine down and slows the fan when it needs to increase the engine speed. If the fan clutch is locked up then it will not let the engine get warmed up. With engine cold and engine off see if the fan clutch allows the fan to spin pretty free with little resistance. If it is hard to turn the fan then the fan clutch needs replaced. For the rough running your engine running colder than normal will build up carbon deposits on the valves and foul out spark plugs. The carbon build up on the valves will absorb fuel when engine is cold and cause runs rough and misfires. You will need to de-carbonize the engine after cooling system repairs and may even need to have a major tune up done to correct misfires. A mechanic like one from YourMechanic can do all the repairs and diagnosis needed for you.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Yielding right of way when obstructed

My apologies but this scenario would be much easier to understand if you were to indicate the direction of travel for each vehicle such as N, S, W, or E. Also, the outcome of this scenario is likely to be...

Not getting no power, no lights, no crank, no radio, no start.

The problem is in your charging/starting system. Most likely, you just have bad batteries (since your truck uses two). A professional, such as one from YourMechanic, can diagnose and repair your starting problem as needed.

Small coolant leak 2003 Dodge Grand Caravan

Hi there - while adding ground pepper to a leaky cooling system may stem a leak, this would seem to require a great deal of pepper! Other "cooling system sealers" may stop a slow leak, but tend to put a...

No start fuel pump not priming during key on sequence also tach is not moving when cranking

Its doubtful that the crankshaft sensor is to blame. The crankshaft sensor is used by the powertrain control module (PCM) to determine injector pulse and ignition timing, not fuel pump operation. The camshaft sensor is used to computer fuel injector...

Car is vibrating when accelerating - 2003 Chevrolet Trailblazer

Hi there. There are several possibilities for the vibration and lack of power upon vehicle acceleration. The missing fuel cap should not affect drivability. Assuming the Check Engine Light has been on for the missing fuel cap, this leads me...

Ran the car with no oil and won't turn on

Hi, thanks for writing in. If you have ran your engine with no oil in it, it is almost a certainty that it will need to be replaced. If it is not starting now due to the no oil issue...

Beeping noise after battery replacement

The horn in the vehicle acts as a switch. Activating the horn energizes a relay, which powers up the electronic horn located under the hood. It is possible that the relay in the circuit has experienced a malfunction, where the...

How do I turn on the auto volume?

When the auto volume is turned on, the volume of the infotainment system will automatically adjust to make up for road, vehicle, and wind noise. To turn on or turn off the setting, follow these easy steps: 1. Press the...

Related articles

The Best Used Cars to Buy For Fuel Economy
Saving money on gas is an important factor to consider when buying a car. The Honda Civic, Toyota Prius, and Ford Fusion all have great fuel economy.
A Buyer’s Guide to the 2012 Ford F-350
With With Ford’s stiffest chassis to date, the 2012 F-350 is one of the most reliable heavy-duty pickup trucks on the market today. With the quiet cabin and plush ride, though, you’ll feel like you’re driving in the comfort of...
The Best Used Cars to Buy If You Live in the Country
Living Living in the country is a whole different way of living. You deal with rough and uneven roads, mud, snow, rain, and ice and you need a vehicle that can stand up to these kinds of conditions with ease....