I would suggest the spider assembly. Maybe the injector is leaking, or fpr. The pump on its own is capable of 100+psi. It holding pressure proves the pump was good. Sorry your having so much trouble, when my fpr went out the engine backfired terribly when i tried to drive it.

 

At this point, you don't know if either pump is any good. Just because it's new, is no guarantee that it's good, especially if it's an aftermarket pump. You're basically right back where you started from and still don't know what's causing the problem. This is exactly why diagnosis is so important. Go back to post #8. Post the pressure reading, and if it holds for at least 10 minutes. The results will tell if the pump is performing properly.

 

Fuel pump checks out fine. Changed the filter while I was down there.

Changed the spider again.
60+ on key. Running at 55.

Idling nice and smooth now. No more miss or popping through the plenum.

Still not right though. Still breaking up at times and stumbling.
Throwing code 44 now. Gas milage is still awful.

 

How does it run for the first minute after you start it?

DTC 44 is indicating a lean condition. The PCM tries to compensate by increasing injector pulse width, (full rich).... there goes your fuel mileage. How many miles on the oxygen sensors?

 

No idea on the 02 sensor. That was my plan for tomorrow, to swap it out.

 

The reason I asked about cold start up is because the PCM ignores the oxygen sensor on start ups, (open loop operation). If it runs good on a cold start, (open loop) then after the engine warms up, the PCM switches to closed loop. If the oxygen sensor is slow or dead, the PCM fattens up the injector and it runs rich. How does yours run on initial start ups?

 

It's staring right up and idles fine. (with the old pump/spider it started a little hard and idled poorly)

I drove it for maybe a half hour or so tonight. It runs fine 95%-98% of the time. Just a couple times when I hit the gas it sputtered a bit like it was doing. And one time on the highway at about 55-60 it felt like I downshifted… engined stumbled and slowed down.* And of course the "Service engine soon" (44) was on. It did seem like the more I drove it the worse it got.



*(not the same feel like the problem I had a couple years ago when the module was crapping out)

 

Did a few things today:
Replaced the oxygen sensor.
Pulled off the MAP sensor to make sure it wasn't plugged up, sprayed some cleaner down in the intake.
Fixed a vacuum leak at the back of the plenum. (one I probably caused changing the spider)
Changed the oil/filter… it was time, plus I was worried about gas in the oil.


Took it for a nice long run tonight, ran great, no stumbles or sputters. I put some gas in it for a little over half a tank and then probably drove a good 30-40 miles. When I got home the gas gauge (digital) was on the same bar as when I left.

Last night before these changes, I drove maybe 8-12 miles? The gauge dropped at least two, maybe three bars (the "smaller" ones down the bottom). So the gas milage is obviously MUCH better. Gas milage was part of the reason it wasn't getting much use, my little car did so much better.

SO…. so far so good. Keeping my fingers crossed.

 

Thanks for the update.