Odd problem, at least to me. Drivability issues, help!

[Jason Reiss]

Last week I went out for a couple of hours to a party. Turned off my '99 L and did my thing. Came out, went to leave, and about an mile down the road the truck started popping and sputtering real bad. Of course, since it was 2AM, I had no choice but to limp it home.

Put my XCal on it and got a P0102 error, along with another one that was MAF-related. So I took off the SCT BA2800 that was on it (only a loaner) and put a stock 01-up MAF on it. Got my tuner (Matt Hill of Matt Hill Motorsports) to work up a new tune with the different meter, and part-throttle drivability is all better again. However, as soon as I lay into the throttle, the truck seems like it wants to die. It's almost like as soon as the blower starts to build boost, a bypass valve or something opens and the truck wants to completely die. Once I let up off the gas pedal, it springs back to life. Tried datalogging it but as soon as I mash it it goes into open loop and we can't get the data we need to try to pinpoint the problem.

Truck does not do this when there is no load - I can leave it in park and it seems to rev up crisp and clean. As soon as I either put it in drive and footbrake it, or take it out on the road to datalog, it starts acting up.

I wasted an entire can of brakleen trying to find a vacuum leak. The truck is no longer throwing codes with the new MAF on it.

Rundown of the parts on the truck -
'99 L
stock longblock
Johnny Lightning airbox w/filter
Accufab oval TB
DynaTech long-tube headers
Bassani catback
No cats, rear O2's have been turned off in the tune

The truck is relatively drivable until I put my foot in it. I have to take a 3 hour drive on Sunday and really need to fix it.

I think I got everything, if not, please ask questions.

I know someone here has to have experienced the same issues. I am a n00b when it comes to these trucks...I bought it only because it's an awesome DD. HELP!

 

[BT2001SVT]

You might wanna check your plugs. the first time this happened to my truck I went through hell trying to figure out what it was. checked the usual trouble spots, plugged in the tuner, couln't get any info, as a last resort, I checked and one of my plugs was shot. Had the same driving problem as you, couldn't get into it without the truck wanting to bogg down or die off like your's is doing.

They're not fun to replace, but worth a look at. Hope you get it figured out.

BT

 

[FireGuy]

Since this is a '99, there are specific problems to consider. Intercooler recall, cracked Y in the fuel tank (noticeable when below half tank), fuel filter, leaking heater hose connection passenger side near the firewall dripping antifreeze on the rear coil packs, coil pack breaking down and lastly, spark plugs.

Any one or more of these can cause the load breaking up problem.

 

[Jason Reiss]

- How would I know if it has had the intercooler recall done?
- Fuel filter was the very first thing I changed last Saturday, after the problem cropped up.
- There is no leaking connection on the heater hose.
- I am heading out to check the plugs right now. Will report back with photos shortly.

This is not a problem that came on slowly. The truck was fine when it was turned off, three hours later it was not. Nothing changed. I even limped it to the store and put a fresh load of fuel in it last night to rule that out.

 

[FireGuy]

Recall information Recall Information - Ford or have a Ford dealer run the vin.


Also, try it with a full tank of fuel, if that works, it is the wye in the tank.

Sudden onset could be the fuel regulator, driver's side fuel rail, use a vacuum pump to see if it holds.

Then it is the dreaded plug change and or a bad coil pack.

 

[Jason Reiss]

Pulled the first two plugs on the passenger side (the easy ones of course), they did not look abnormal, they looked like 25,000 mile plugs.

Since it's 40* here in Michigan and it's ****in' cold outside, I had my girlfriend shoot a video of it so you guys can see what I'm talking about.

[nomedia="http://www.youtube.com/watch?v=b20PG9lrM_E"]YouTube- engine problem, '99 Lightning[/nomedia]

 

[BT2001SVT]

I feel your pain, bustin knuckles in the cold ****ing sux:cuss::cuss: My crap plug was all the way in the back, god was punishing me for something. I hope if it is a plug issue you find it sooner than later.

Good luck

BT

 

[Jason Reiss]

I have confirmed that there are no open recalls on the truck also.

Heading back out to try and get the rest of those plugs out.

 

[Jason Reiss]

all of the plugs are changed and I have also jumped the FP resistor and the fuel pump hi-lo switch and regular FP relay, and the problem is still there.

If I watch the boost gauge, as soon as the truck starts to build boost is when it starts to die. I can shoot another video of it if that will help.

I am guessing it's time for a new pair of fuel pumps and the stainless y?

 

[Digby]

From the sound track of the Vid you're GF took it seems like the coupler in the SC snout has let go and there it little or no drive to the rotors when under load.

 

[Jason Reiss]

Resolution:

I dropped the tank on Friday afternoon. Once I got the hat out of the tank, I found that the hose had popped off the top of one of the pumps, so the other pump was just backfeeding through the y-fitting. I went ahead and replaced the pumps with a pair of Walbro GSS342's, used all new submersible fuel hose, new clamps, and replaced the y-fitting with a stainless one I found locally.

Thanks to my friend Rick Riccardi, who manages the parts department at Downs Ford, and helped me out with getting me all of the new parts that are on the truck - the MAF and the pumps were shipped/received promptly.

What a pain in the ass.