91 Ford E150 v8 302 EFI - jerks/stumbles/balks on road

ANY suggestions will be appreciated.

Right after I replaced a leaking float in my forward gas tank, the check engine light started coming on and the engine began intermittently balking (cuts out/in). Fuel injector cleaner and dry gas in the gas tanks didn't help. So, I replaced fuel pump assembly, the vapor control valve and grommet and the lock ring rubber gasket in the forward fuel tank. However, the check engine light still lit and the balking continued.

So, I replaced the distributor cap, rotor, pcv valve, air filter, oil filler/air intake filter, and the in-line fuel filter. Gap and plugs 8 through 3 appear OK, so I skipped Plugs 2 and 1 for now.

Now it takes longer for the check engine light to come on (4-10 miles) intermittently. It still balks, which happens out of synch with the check engine light. It seems to happen more when the engine has warmed up, but temperature and oil guages read normal. There is a distinct loud clicking sound when the engine balks, which may be an effect, not a cause. :confused:

Using expensive trial and error, some next steps are: (0) call Car Talk (NPR radio show Saturday mornings) when they get back from vacation, (1) replace the two gas tank caps, (2) replace the plug wires, (3) replace the in-fuel-line canister (attached to the van’s frame forward of the forward gas tank), (4) replace the in-line fuel pump forward of the forward gas tank, (5) replace the coil, and/or EEC microprocessor and/or ignition module (6) replace the throttle position sensor, (7) replace the MAF (MAP?) sensor, (8) replace fuel pressure regulator, (9) check other emission control components such as EGR, air and bypass control valves, (20) take it to a garage that can plug into and read the diagnostic system, (999) take it to a dealer.

My E150 (300 ci, inline6, automatic) balks when cruising under little load between 30 and 45 mph. The previous owner told me that it did this to him. He had the injectors professionally flushed several times and replaced the injectors once. Each time the problem went away, but came back in 15-20k miles. I don't know if your balking sounds the same?

Hope this helps.

My E150 (300 ci, inline6, automatic) balks when cruising under little load between 30 and 45 mph. The previous owner told me that it did this to him. He had the injectors professionally flushed several times and replaced the injectors once. Each time the problem went away, but came back in 15-20k miles. I don't know if your balking sounds the same?

Hope this helps.

Does the problem still exist?

If not, what was the last thing he did?

Thanks.

UPDATE:

The problem still exists.

Previously mentioned repairs:
-twice added fuel injector cleaner and dry gas to the gas tanks,
- replaced fuel pump assembly, the vapor control valve and grommet, and the lock ring rubber gasket in the forward fuel tank,
- replaced the distributor cap, rotor, pcv valve, air filter, oil filler/air intake filter, and the in-line fuel filter,
- check the gap on plugs 8 through 3, skipped Plugs 2 and 1 for now,

New repairs:
- replaced the distributor with a remanufactured one,
- my timing light stopped working, so I replaced it to reset the timing,
- replaced the ignition module,
- replaced the ignition coil,
- replaced the gas tank caps
- finally was able to use Advance Auto Parts free loaner code scanner which now tells me that voltage is low on the TPS (throttle position sensor) (KOER code 63).

I purchased a new TPS ($30) and will now install that, however, the Haynes manual says after I install it that a Dealer must adjust it, even if I put the new one in exactly the same one as the old one. That probably means $100+.

UPDATE:

The problem still exists.



The problem is now fixed.

After several tries using the code scanner that Advance Auto Parts loans free of charge, I finally got a code when the problem was actually occurring. The code description was low voltage on the TPS (Throttle Position Sensor), which is attached to the bottom of the throttle body. When I removed the TPS, it had one wire with no insulation (possibly a ground wire?), another wire with the last 1-2 inches of insulation missing, and a third wire with good insulation. The replacement TPS had insulation on all three wires. There was a lot of carbon and possibly oil buildup in the intake manifold for a van with only 49000 miles, hopefully the result of the TPS, which may have been bad since I bought the van in 1991.

The engine ran noticeably smoother as soon as I replaced the TPS (not an easy task). The engine light came on for a second after the first mile or two, but hasn't been on since then. The engine balking/hesitation/cutting in and out quit. However, I will reserve final opinion until I get a few hundred miles on the new TPS.

Incidentally, the Haynes manual said that the TPS, after replacement had to be adjusted by a dealer. However, this particular TPS was listed as non-adjustable on the Internet at Advance Auto Parts, where I bought it.

So, this problem apparently had nothing to do with my replacing the float, then the fuel pump assembly in the forward tank. It was just a very misleading coincidence and I fell for it.

Unbelievably, as soon as I replaced the bad TPS, the turn signal suddenly quit working, the battery went dead, and the fuel guage started wandering back and forth from three quarters full to empty. Those problems now appear to again have just been a coincidence and had nothing to do with my replacing the TPS. The battery proved to be bad according to Advance Auto Parts testing machine. The turn signal problem was due to a bad flasher, which happens to be separate from the hazard lamps flasher and is on the back of the fuse panel and hard to find. The Haynes manual said it was behind the instrument panel.

The moral of the story is don't put a lot of weight on problems occuring close together in time. There may be no cause and effect. Twice I spent a lot of extra time and money betting on what turned out to be coincidences, instead of looking first for the simple and usual causes.