She runs perfect when i first start her up, RPM's drop down to about 850 after about 10 seconds and stay there until whenever. No sign of sputtering

No signs of sputtering or shakiness while I'm driving either. It's only after I've been driving and then pull up to a red light after the engine has warmed up.

It's not a violent shake or sputter, just annoying and it's about every 5 or 6 seconds.

Anyone have any ideas? thanks in advance!

Brandon

::edit:: it's a 94xlt reg cab long bed 4X4 with the 5.0 auto

 

sounds like a misfire or a vacuum leak.

 

What's the fuel pressure when it sputters? What's the plug gap? How many miles on the wires, cap, rotor, coil, ignition module? Are the wires routed properly?

 

Do you have a check engine light on? Even if you dont, pull codes anyway.

 

yea see if there are any codes. does the cel work?(should come on by turning the key on with engine off) are you using the a/c? if so maybe its low on freeon and the compressor is locking and unlocking every 5-6 seconds. it may be running rich. first things first check for codes.

 

have't tested it for codes, nor do I know if the previous owner had any troubles with it. Yes the CEL works. Yes I do use the A/C , it blows really cold but I have noticed that the compressor will click on and off about 4 or 5 times while at a light, but this is in addition to the stuttering. I will take it in to auto zone or something to pull the codes and post them up for you guys to pick apart haha.

b

 

Stay OUT of the zone. Those morons don't know anything about EEC-IV codes. Get a paperclip (jumper wire) and read the 7th post in this thread:
http://www.fordf150.net/forums/viewtopic.php?t=71346