Hey Guys,

First time on this forum and I am hoping there are a few guru's who can help me diagnose an engine problem.

The main symptom is during acceleration from a stop the engine seems to
struggle with power until it gets to around 3500 rpm. Once it gets up in rmp's it catches all of a sudden and you get a sudden power surge.

Up until that point it struggles bad to get going. Especially when I am pulling
my show car on my trailer. I can barely get it going.

I recently had the motor checked out and everything seems to be in order with no error codes from the ECM.

Another potential symptom is after the motor has been driven for a while on the highway and you slow to a stop the motor wants to die or the idle gets very bumpy/rough.

I have also noticed that when I first start the truck regardless of hot or cold it is rough idle until I revv it a couple times, then it smooths out nicely.

I recently put a new idle control sensor on it so that's not the problem.

Anyone have any ideas.

Please let me know!

Thanks.

Michael from Arlington, Texas

 

What is the make, model, year, engine, and mileage of the truck?

Sounds like it is need of a tune up and a TB cleaning, but, the above info would help narrow it down a tad bit more.

What was the reason for replacing the IAC?

 

The Truck info:

1997 Ford F150 Flareside
4.2L V-6
Automatic
96,000 miles

I recently had everything checked out and all I needed was
new plugs.

I had the IAC replaced because it was bad and causing a very rough idle.
They also found a vacum leek in one of the hoses to the IAC.

The symptoms now are completely different than before the new IAC.

Hope this helps!!

 

So, plugs were replaced and wires were not? When it is dark out, start the truck and look under the hood for any arcing of the wires.

When was the last time the fuel filter was changed?

What plugs were used?