He does mention that he's got a 3.5L DOHC. This engine may have been available in other countries in 97. So your initial thought may still apply.

Joel, CA

My 96 3.5 was running rough also. I had a hell of a time finding out why. I finnaly narowed it down to the insulation boot at the end of the coil pack. The spark was shorting out to the head. Pull the coil pack and look at the end. See if it's scorched in one or more spots. I couldn't just replace the boot at the end of the pack. I had to get a new coil. Hope this helps.

Does your truck have a distributor? Or does it have coil packs? I just saw picks of a '97 3.0L from Venezuela that had a distributor. If you have a distributor, it is very possible that it is screwed up.

Winston
sorry about the engine confusion, I do have the DOCH engine, it seem that they was selling old 1996 here in the name of 1997. anyways I have changed my Sig to 1996. <img src="/forums/images/graemlins/smile.gif" alt="" />

So what is the issue about the betterfly valves???????
and about the plugs, My plugs were changed by the dealer alone with the timeing belt. So I didn't see them <img src="/forums/images/graemlins/frown.gif" alt="" /> and the timeing belt is origenal aslo.

Conner:
I am sorry, But I don't have the right tools to do the compersion test or the vacume test. and I don't have the Dignosis tool to pull the codes <img src="/forums/images/graemlins/frown.gif" alt="" />
But thanks for you info, I might go to a local shop to see the codes

Squaremeal:
Where can I find the coil packs boots to check them????

Winstone:

I think mine doesn't have a distributor.


thanks guys

I am going to atempt to post a picture for the first time so I apologise in advance if it doesnt show up. And I would like to thank Justice in advance for the great picture. If you look between where you add oil and check the oil, there is a black plastic cover just below it. I think 6 or 8 bolts hold it on. If you remove those you will find the three coil packs. Each is held on by two bolts and some wires are atached to it. Unplug the wires and undo the bolts and the coil should come right out. I would just look at one then put it back and reconnect it before taking off the next just so you don't get the wires mixed up. Hope this helps.
Jared

Thank you Squaremeal
I will take a look as soon as possible.

abd about the other side of the engine: should I attemp to open it as well. Because it does not look easy to open the other side.

I will keep You updated with details as they be available

OK, see that diaphragm just below the intake plenum? Disconnect and plug the vacuum hose connected to the diapragm and see how the engine runs. That diaphragm controls the intake manifold butterfly valve (variable intake).

Hey, I'm a total know-nothing, but this sounds like pretty violent shaking.
I only ask because I heard this on Car Talk once:
broken motor mount?

Don't bother with the right side of the truck. It's only spark plugs and wires under there. The three coils under the plastic on the left side delivers the spark to two plugs. One on the right side and the one right under the coil. What I think is happening is that the boot right under one of the coils has lost its insulation value. When you pull the coil the boot that covers the spark plug will come off with it. Look at where the spark plug goes into the hole of the boot. If it looks as though the spark is going through the rubber into the metal right next to it then I would say that is where you are getting your hesitation.
Let me know how it goes.
Jared

I am sorry I didn't replay earlier, I was busy with University regesteraion stuff.....

anyway Winstone...:
I removed the vaceum hose and nothing changed.
I even did it while the engine was running but no difference. The engine still has that hesitation.


Squaremeal:
How many bolts are there??!!I attmpted to remove the plastic cover but whe I counted the bolts I saw 5 only!!!!
Are there any bolts that goes under the intake manifold??
I nead your confimation about the number of bolts?