High Idle, Pulsing Idle?

[MazdaGreg]

Alright, here we go...

First off, did you buy these parts somewhere that you can return them? I know that's got to be expensive...

As far as your water pump theory, No bloody way. Water pump's either work or they dont. If your running hot, it could be a whole host of other issues, that you'll have to diagnose, but i won't get into those here. Just know that if your pump isn't leaking, don't change it.

Water pump is almost no drag whatsoever on an engine. That's not the problem.

It sounds to me that you might have something going on that will be harder to diagnose over the chat session. If you can return your parts, do it, and take it to a diagnostic's shop. Trust me, throwing any more parts at it will probably end up in disappointment. From what you have tried, it sounds to me that you've hit the main points. Now it comes down to having the right equipment, like a scope, engine scanners, and all the like.

From the prices of those parts, it sounds like you bought them at Autozone or somewhere comperable. Return them, and go get your truck diangosed. I hate to say that, because i hate to give up, but this problem is a tricky one...

Good Luck,

 

[gss]

I just can't imagine running in 4 wheel drive at 70 MPH. If it is that bad on the road, please slow down. That can't be good on the drive train.
My daughter's 96 was running real rough last year and it had a cracked head. If that is the case you are not to get running any better. Get a vacuum guage or have someone run a vacuum test on the engine.
Heads are expensive but, what isn't these days. I had Ford dealer do the repair so I got bit big time.

 

[SolidGoldCaddy]

im trying a thermostat tomorrow...

 

[SolidGoldCaddy]

great fixed it, cost me 12.00, and it was a thermostat, and top off the coolant...who knew....the cpu was bringing the idle up to try and circulate the coolant because it saw the temp gauge hot, well the thermostat was stuck shut, so it couldnt flow anything through....and kept getting worse as the air temp got higher, so i got a new therm. and filled the coolant up, and bam, runs and idles at around 6-700.....thanks to all who helped, and to thos of you who had this same thing go on, check the obvious and most basic things first, dont throw 160.00 bucks away on sensors like i did on a hunch....

 

[south59]

Glad to hear you got it fixed, I actually bought a thermostat today and am planning on putting it on tommorow, wish me luck!

 

[ray11299]

i just got here...

i just joined today so i just read your whole deal and i must say that i was out of ideas too. i had a problem just like yours and it ended up being one of my vacuum tubes having clay and dirt in it. im going through it again but the thing is i havent been muddin in like three months. im gonna try the thermostat tommorow because of this post so thanks!