94 Ranger Hesitates Once Hot

[94RangerGuy]

I have a 1994 Ranger with ~195,000 miles. It seems that when the engine is under load (typically when climbing a hill in 5th gear or if cruising then I depress the pedal to accelerate when passing etc.) the engine will give a periodic hesitation (stutters kinda) - I notice this once it gets up to temperature. The problem will go away if I downshift to 4th gear where the RPMs are higher. I have had this problem with the truck twice before. The first was about 2 years ago (~160,000 miles). I replaced plugs and wires and the problem went away. Then about 6 months ago (~185,000 miles), again, I replaced plugs and the problem went completely away.

Any ideas? I was told told to change the EGR valve, but to be honest with you I can't even find it in my truck.

Thanks!

 

[Earl43P]

I see no reason to suspect EGR, but you can rule it out by simply pulling the vaccum line off of it. Try driving it that way to see if it changes. It'll light the CEL. EGR valve looks like a mushroom cap, should be connected to the DS exhaust manifold by a pipe.


Sounds like you may be fouling plugs, based on your history. Pull them, clean and gap or replace. Would help to know their condition when pulled (wide gap, burnt electrode, black and oily, grey sooty, brown, etc.) Make note which plugs look bad for future reference.

 

[94redranger]

94 4.0 dont have EGR.

 

[Big Jim M]

Might could be the temp switch.. Or could possibly be a fuel filter..OR maybe the plugs you are purchaseing aren't as good as the STOCK plugs were..Put a set of stock plugs and see what happens..
Big Jim

 

[94RangerGuy]

Thanks for the help guys. I just wanted to give you an update. I dropped the new plugs in (Motorcraft Plat. from the Ford dealer @ $8.XX each) and the truck is running great again. In inspecting the old plugs, they looked very good still. They were properly gapped (all were .052 - .056), not burnt...just looked good (old ones were Autolites). I also replaced the plug wires. In the process, I had two that separated from the boots. I think the last time I replaced plug wires, I used a cheap wire (Xacts from Advance Auto). In fact the last time I replaced plugs I had one pull apart one me, but I repaired it.

Anyway, thanks again for the help!

 

[Big Jim M]

Motorcraft wins again.. A very good lesson on sparks ain't it?
Big JIm

 

[parson2008]

my 93 does the same thing, its not coolant temp sensor, or egr. and i am runnin autolite plugs. so im replacin them