Misbehaving ISB

[Sean Flanagan]

Hey all you Turboheads!

My 98. 5 ISB is acting up right before I go on a road trip. '

Here's what it does:
- Misses at idle (only when hot), missing a beat about once a second (irregular)
- Cuts out occasionally (every 10 minutes or so) for about a second, only under light throttle. Still runs great at full throttle.
- Check Engine light came on but went out after a while

Soooo... What do 'ya think guys?

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98. 5 2500 QC LB 4x4 5spd, white. BFG 285x75x16
Cummins 24v w/ TST PowerMAX w/EGT and Boost gauges on A-Pillar. VanAaken CPC. K&N In the factory air box. Stock Injectors, Stock Exhaust (Geno's Muffler Eliminator). Re-routed breather stink tube, 2WD-low kit, SnugTop, JJ Stainless Running boards, Tow Hooks, Bushwacker Street Flares, and a Cup Smoothie.
78,000 miles (11/17/00)

 

[Vaughn MacKenzie]

Could be your TPS (throttle position sensor). The one on my '98. 5 died at 49,000 miles and it would cut out 3 or 4 times a day where the engine would go to idle and not respond to the throttle.

Anothing thing, it never hurts to check your fuel pressure to make sure the lift pump is working OK. If my truck was starting to act up I wouldn't be able to drive with peace of mind not knowing if my lift pump was OK.

On the same note, have you changed your fuel filter lately or checked for water in the canister? You know this is the time of year to have fuel problems.

Vaughn

 

[Sean Flanagan]

Vaughn,

How did you know for sure it was the TPS? I did you just replace it and see?

I'm replacing the fuel filter tonight so I'll check it out.

I'll see if I can scrounge up a temporary test gauge to check to fuel pressure. I have a real one with 2 senders on order but it isn't here yet.

 

[Fuzz]

Sean,
I live in Happy Canyon,Exit 187 ofI25.
I have a SW Fuel Pressure gauge on mine.
2 senders before and after filter.
Mines a Y2K. The senders just bolt on to test
fittings with -4 fittings. The point of all this is. . If you think we could make it work on yours to check the pump,would be easy to take off one mine and try on yours.
Fuzz

 

[Archive]

<font color=blue>Just curious, did you try unhooking you PowerMax? Does it do it with the PowerMax on and off? Could be traced to the "electrical" connections somehow. I do know there were some problems not too long ago. I believe Steve StLarent had trouble with his.

 

[Sean Flanagan]

Now that I have posted this message, the cutting out problem won't reproduce itself. It didn't matter that the box(es) were on/off disconnected or whatever.

Although, no matter what I do, it always has a slight miss at idle when heated up.