Losing Power Intermittently. Grasping at straws here.

[ascCapri]

I am not sure where the old thread went since last night, but I replaced the rattling O2 last night with another new one.....seems to be the first thing that has made any inkling of a change. It runs better now, but when I surprised it, the truck still bogged for a second. I will replace the other O2 tonight, and see what happens. I guess I waited so long to look at these as a possible culprit because I just bought them new in the Spring.

[92coupe]

You really need them things? Lol!

[ascCapri]

Well, this is wierd....burned up another O2 on the Driver Side...could this be caused by 1 or several bad injectors? As I said, the plugs are a hair bit white across the board, all 8. I have no problem changing the injectors, but I just want to make sure there isn't something else that could be the culprit.

Here is some background from the original post.

Truck has full 89-93 Mustang harness. EFI 302 with bolt-ons. Timing is at 10deg, 24 lb injectors and meter, all plugs look lean.

The car started to suddenly lose all power when it was cold, kicking and sputtering, and I was never really able to throttle through it. If I turn the key off and back on real quick, I'm back to normal. If I am on the highway, and just continue to allow it to run like crap, after roughly 2 minutes, the truck will immediately run perfect, like it snapped out of it's funk. Now it seems to do it whether cold or hot. I will drive for ~2 minutes, and it will started sputtering....not violent, just as though I lost fuel pressure or spark on a few cylinders. I can maintain a constant RPM, but no accelerating. Turn key off and on, back to normal for 2 minutes, and so on and so on, making a trip to White Castles more and more frustrating.

From my experiences with 5.0's, it feels like a fuel pump going.....however, my electronic fuel pressure gauge remains pegged, only oscillating slightly with bumps in the road. Here's the list of things I have tackled in order.

Different Cap, wires
Different Distributor and ignition module
Different Fuel pump relay
3 Different TPS's
Different IAC
Cleaned O2's
Different Coil
Additional Ground on Engine to frame
Different MAF
Different A9L (suspected bad, as my TPS voltage would stay constant at 4.95, car still ran same, but wouldn't hold a TPS tune, and obviously read way high. Went back to original A9L, TPS is fine)


All parts were used from my shelf. All were installed one at a time, followed by a trip around the block, and It would usually start within 1/2 mile.

I replaced the TPS with a brand new unit, and set it to .98-.99 as I did with the others.

I have a set of 30's and meter, this is my next step....I think. Could I have several bad 24's? Again, I tried a different meter, but cannot ohm all of the injectors without taking the intake off anyways.

Again, O2's fixed the problem the first time so I assume this rattling O2 will fix it again, temporarily. Trying to find the root cause.

[todd86]

I'd try relpacing the EEC relay