Stuttering

[Sampson]

When first start my truck up it run a little rough like there is a miss fire. When I go and drive away it continues to do it for a minute or 2 until it warms up some. If i rev it while parked it it just stutters like it doesn't want to rev up. When I'm driving it doesn't have to be under much of a load before it starts to really stutter. It will still accelerate but stutters more the more gas I give it. I did have a cel go off a couple of weeks ago and it was a miss fire on number 6 and I had similar symptoms. After I drive it a bit it runs just fine and won't stutter no matter how much load I put it under. All the plugs and wires are good and fairly new but the coil pack it original. It has about 125xxx. its a 99 ffv. Should I replace the coil pack and go by there?

Thanks Pat

 

[JP02XLT]

Coil Packs usually fail completely on two cylinders at a time and generally set a misfire code when they do. Since you said it only does this when its cold I would replace the temp sensor for the ECU, it may be reporting the wrong engine temp to the ECU and causing the problem, They seldom set a code unless they totally fail. You can check the readout with a scanner, check it with the truck cold and hot, cold temp should be near ambient, Hot should be in the 195-205 range. Since it reported a CEL code on cylinder 6 I would really look close at the plug and wire on 6, maybe the wire has a nick in the insulation and arcing out, pull the wire off the plug and see what kinda spark your getting. Sounds almost like you have 2 symptoms your chasing.

JP02XLT

 

[Sampson]

Thanks JP. I think I will go ahead and just replace the coil pack since its the original. I will check all the plugs and wires. I assume you are talking about the coolant temp sensor and not the air temp sensor? Should I replace both and see what happens. Also where is the coolant temp sensor located, is it on the radiator or water pump?

Thanks Pat

 

[kevinsranger]

check the intake tube between the maf and the throttle body for cracks from age and dryrot, if there is a hole or crack, run some electrical tape around to see if that solves it

 

[JP02XLT]

Coolant temp sensor for the ECU is usually in the intake manifold near the water neck

JP02XLT

 

[McCormack]

Even though it hasn't thrown a code I wouldn't rule out the DPFE sensor being bad.

 

[Sampson]

Thanks guys. I will replace the coil pack, coolant temp sensor and plugs and go from there. I think I will clean the maf and intake tube and give it a look over.

Thanks Pat

 

[Viper Command]

too cold of a spark plug or not using motorcraft platnum. I had the same problem in my '02 2.0 escort.

 

[Sampson]

Ok i replaced the ignition coil, coolant temp sensor and cleaned the maf and still have a misfire on 6. I drove it today and it ran just fine. Before today the last time I drove it was Saturday night and it missed a little bit but drove good for the most park. I drove it Friday night for the first time in 6 days and it drove terrible, It got better once it warmed up but was still missing. What else could it be?

Thanks Pat

 

[Spitfire1975]

My 86 2.9 is doing the EXACT same thing, and has been for the last two years. I have changed EVERY sensor, checked for loose wires and bad grounds, checked for vacuum leaks (and still changed all of the gaskets and hoses I could find), changed the high pressure fuel pump (about to do the in-tank pump), changed the fuel pressure regulator, gave it all new exhaust and probably numerous other things I can't think of.

AND STILL IT DOES IT.

I am starting to think it is either the computer itself, something to do with fuel return lines or the Dark Lord himself possessing my truck.

 

[Spitfire1975]

Oh yeah, I also change the coil, distributor pickup, Plugs, wires, cap, rotor, etc...

 

[locovaca]

I would rule out something mechanical. Get a compression test done. Testers are cheap and it's not hard to do.

 

[Sampson]

I will do a compression test this weekend. I have a feeling they won't all be equal.