1998 5.4 Shudders under throttle tip-in

[CAMartin]

Hey, all, just found this site...

...and I have a problem with my 1998 XLT. In wet weather (no shortage of that up here in Washington), my Expy will get a shudder when adding light throttle. It has had engine codes for COPs come up, and I've replaced a couple...but sometimes it seems erratic, and I've heard that some hoses may rot in these, and/or that the computer (which is pretty old, now) may be having issues. I'm open to suggestions, as I love the truck...but I'm on a fixed income at the moment and need to figure out as much as possible before paying a mechanic.

 

[1955moose]

Well welcome to the site. First thing, how many miles on SUV? How many miles since any tune-up? If you read other threads on stumbles or erratic accelerating, or idle, their are a few things you can do. Number 1 is to plug into your diagnostic port, and bring up any dtc codes from your computer. After that simple things to do are 1, pick up a can of Crc mass air flow sensor cleaner. Spray the electrical wires of the sensor. 2 run a fuel pressure reading at Shrader valve to be sure your fuel pump is putting out at least 35 psi. Beyond that simple things like clean air filter, spark plugs, and boots next. Start with the basics first. Keep us posted.


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[docraymund]

Yes change all plugs and coils. Replace air filter.

 

[ldutton6]

Check the Mass Air Flow Sensor.. Mine had some excessive dust and what not on it.. This to me sounds like a coil... Do this...

Open the hood at night and see if you see any arcing from the top of the coils.. If you don't it doesn't mean there not bad though... Take a bright flash light and point it at the top of the each coil... I bet there is a crack on one or a few... I bought my 99 expy 5.4 liter and I had to replace 4..

Now, here is a question for anyone out there... On ebay you can buy all 8 for a really good price... Anyone have experience with this? If they are good go on ebay and buy all 8 and replace them all... If you are slightly handy you can do this. Put dielectric grease on all of them. The plugs are a bear to do in the back but I did do mine. I used like 3 elbow sockets and a few extensions and it worked well.. I'd bet you this is the problems... mine did the same thing before I did a tune up like this. And, now I'm good.

http://www.ebay.com/itm/New-Ignitio...ash=item3a8bca6d5f:g:7AYAAOSw~1FUV9uq&vxp=mtr

 

[1955moose]

Check one of the threads from about 2 weeks back. Their was a guy that had good luck with coils he bought online. They were cheap price too, about $80.00 for all 8. I agree with the full tune up, but 1, he's on a tight budget, and 2 , the plugs are a S.O.B to do. Was saving the worst for last.


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[CAMartin]

All the codes I've gotten are COPs, and even on ones that I've previously replaced...which is why I suspect the computer.

Also, does anyone have any brilliant ideas about how to get at the coils on the back 4 cylinders? They're not terribly accessible with basic hand tools, so I'm open to ideas...including the MAF cleaner, I have some of that and will try it tomorrow.

 

[stamp11127]

There are plenty of threads on here where members have switched to the cheap cops, higher output cheap cops and cheaper cops. In the end they have usually ended up crying the blues about them and bit the bullet for OEM cops.

So it is up to you if you want to roll the dice on the "one hung lo" specials.

 

[1955moose]

The same dtc codes coming up can be cheap coils, worn boots from coils to plugs, or carbon arcing around boot to plug. Before you condemn the new coil you replaced, swap it with one of a known good one. and see if code switched to that cylinder. I know $75.00 each dealer coil is high, but like stamp said, they always work!


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[ldutton6]

The back coils are not hard its the plugs... Basically just LONG extensions, elbow sockets and labor. Took about 2 hrs to do plugs and coils.

 

[ldutton6]

Well, I went to advanced Auto and got my coils... They were like $45.00.

 

[1955moose]

Were they $45.00 each?


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[CAMartin]

Something I neglected to mention: the problem gets worse and/or is more likely after rain. As I live in Washington state, there's a fair amount of that to be had...and the rainier it gets, the worse it gets.