Yesterday my truck starting juddering heavily during acceleration, the closest way I can think of to describe it is like a misfire. But I thought a misfire would be constant (whether on the gas or not).

The juddering only happens when accelerating, and it appears to only happen around 1100RPM (or when the engine is under a heavier load, eg: going up a hill) any idea's what this could be?

The plugs were changed about 3 months ago, and looking under the hood I can't see anything obvious. Hoping this is not going to be costly

 

What is the year of the truck? Engine size?

 

Sorry, that would have really helped!! its a 2000 F-150 with the 5.2V8

 

Ok I had the truck in the shop yesterday, hooked up to a couple different code readers and it's not showing any codes at all. Nothing. Had the mechanic look over it, and he could not find anything. He said that it (at this point) is not worth me spending money just to eliminate possible problems (I agree on that!!) and to just keep driving and see if the check engine light comes on, at which point hook it back up to the code reader.

On the drive to work this morning it has not juddered once, it feel's a bit gutless when accelerating, but always has (and having never driven another one, I don't know if this is normal). So any ideas?

 

Find the condition that forces the SHuddering, then hammer on it until you finally get the computer to identify a misfire.

What plugs were installed? These 5.4 s are picky about certain brands...

Your symptom is of a typical misfire, usually due to a COP starting to break down.

Steve

 

Thanks Steve, IIRC the plugs that were installed were Autolites (if not Autolites then they were Motorcraft) When I leave work today I will take a different route home (cross country so more work on the engine than sitting on the freeway for 50 miles) and hope that I can get an engine light to come on.

In a way I am hoping it is just a misfire and a COP as the COP's are something that I can replace, and I don't think all that expensive either. Thanks again.

 

Find a nice, long uphill slope. Drive just fast enough to shift into OD (40-50 mph). Then, intentionally lug the engine by feathering the gas pedal so it doesn't downshift.

This seems to put the greatest stress on the ignition system and usually will cause the misfire to show up (if it's going to).

Steve

 

Don't discount the transmission as a possibility.
Have you had the transmission fluid checked or changed recently.

I have known of a few guys who changed the transmission fluid and it cleared the problem.
Apparently torque converter or maybe a hydraulic shift switch.
I dunno but worth considering.....

 

Yeah, it could be TC shudder, however, unless you have a scan tool that can read mode 6 data, it'll be tough to see if it was a misfire or not.

Under the driving conditions I described, misfires will usually be aggravated, often to the point of getting a code so that a basic scan tool can read the faulty cylinder.

Trying to make things possible for those not well equipped...

Steve