weird mis 93 2.4

93 Pickup 2.4, 211,000 miles, manual trans, 2wd.

The truck will run fine for hours, then while driving at any speed it
will cut out as if the coil wire were arcing, then back to running fine.
It's not dependent on RPM, speed, or throttle position although it
hasn't happened at idle. It starts well and runs smoothly.

What I've done so far:

New cap, rotor, wires, plugs.
Ohmed pickup coil in distributor OK
Checked pickup coil air gap. OK
Ohmed high tension coil OK
Replaced high tension coil and ignitor with known good one.
Checked for computer codes. None
Checked timing. OK
Checked connections on coil, distributor, computer.
Adjusted valves.

Any ideas?

Q

Q wrote:[color=blue]
> 93 Pickup 2.4, 211,000 miles, manual trans, 2wd.
>
> The truck will run fine for hours, then while driving at any speed it
> will cut out as if the coil wire were arcing, then back to running
> fine. It's not dependent on RPM, speed, or throttle position although
> it hasn't happened at idle. It starts well and runs smoothly.
>
> What I've done so far:
>
> New cap, rotor, wires, plugs.
> Ohmed pickup coil in distributor OK
> Checked pickup coil air gap. OK
> Ohmed high tension coil OK
> Replaced high tension coil and ignitor with known good one.
> Checked for computer codes. None
> Checked timing. OK
> Checked connections on coil, distributor, computer.
> Adjusted valves.
>
> Any ideas?
>
> Q[/color]

Have you checked fuel system and throttle body for clean?
Some plug wires will cross-fire if laid on top of each other and not
seperated with looms.
If your wiggle ignition (key) with engine running does it affect? Sometimes
ignition switch will cause this when starting to fail.
Had a Chevvy once that would die randomly and restart right away, found a
shorted wire where it went through a hole and grommet had broken away. Try
bending/moving wires with engine running for possible short.
Check all grounds, some may be hidden under battery tray, to make sure they
are good. Remove, clean and reinstall. Also check all plastic plugs for
sensors and etc. for good contact. Lube with dielectric grease when
re-plugging them.
HTH, Dave

Thanks David, good suggestions.

Cleaned the throttle body a few weeks ago.
Plug wires are new in in the separating thingees.
Ignition switch, never thought of that.
Grounds cleaned as well as battery terminals.
Sensor plugs cleaned and checked.

It appears the problem was the fuel pump. Maybe not making enough
pressure or occationally sticking? Last time it started missing I
noticed a slight ping like a lean running engine. I put in a pump and it
seems to have cured the problem. I'll find out for sure next week when
I'm driving it on a 1500 mile trip.

Q


davidj92 wrote:
[color=blue]
> Have you checked fuel system and throttle body for clean?
> Some plug wires will cross-fire if laid on top of each other and not
> seperated with looms.
> If your wiggle ignition (key) with engine running does it affect? Sometimes
> ignition switch will cause this when starting to fail.
> Had a Chevvy once that would die randomly and restart right away, found a
> shorted wire where it went through a hole and grommet had broken away. Try
> bending/moving wires with engine running for possible short.
> Check all grounds, some may be hidden under battery tray, to make sure they
> are good. Remove, clean and reinstall. Also check all plastic plugs for
> sensors and etc. for good contact. Lube with dielectric grease when
> re-plugging them.
> HTH, Dave
>[color=green]
> > Q wrote:
>> 93 Pickup 2.4, 211,000 miles, manual trans, 2wd.
>>
>> The truck will run fine for hours, then while driving at any speed it
>> will cut out as if the coil wire were arcing, then back to running
>> fine. It's not dependent on RPM, speed, or throttle position although
>> it hasn't happened at idle. It starts well and runs smoothly.
>>
>> What I've done so far:
>>
>> New cap, rotor, wires, plugs.
>> Ohmed pickup coil in distributor OK
>> Checked pickup coil air gap. OK
>> Ohmed high tension coil OK
>> Replaced high tension coil and ignitor with known good one.
>> Checked for computer codes. None
>> Checked timing. OK
>> Checked connections on coil, distributor, computer.
>> Adjusted valves.
>>
>> Any ideas?
>>
>> Q[/color]
>[/color]

Glad you found the problem.
Dave

Q wrote:[color=blue]
> Thanks David, good suggestions.
>
> Cleaned the throttle body a few weeks ago.
> Plug wires are new in in the separating thingees.
> Ignition switch, never thought of that.
> Grounds cleaned as well as battery terminals.
> Sensor plugs cleaned and checked.
>
> It appears the problem was the fuel pump. Maybe not making enough
> pressure or occationally sticking? Last time it started missing I
> noticed a slight ping like a lean running engine. I put in a pump and
> it seems to have cured the problem. I'll find out for sure next week
> when I'm driving it on a 1500 mile trip.
>
> Q
>
>
> davidj92 wrote:
>[color=green]
>> Have you checked fuel system and throttle body for clean?
>> Some plug wires will cross-fire if laid on top of each other and not
>> seperated with looms.
>> If your wiggle ignition (key) with engine running does it affect?
>> Sometimes ignition switch will cause this when starting to fail.
>> Had a Chevvy once that would die randomly and restart right away,
>> found a shorted wire where it went through a hole and grommet had
>> broken away. Try bending/moving wires with engine running for
>> possible short. Check all grounds, some may be hidden under battery tray,
>> to make
>> sure they are good. Remove, clean and reinstall. Also check all
>> plastic plugs for sensors and etc. for good contact. Lube with
>> dielectric grease when re-plugging them.
>> HTH, Dave
>>[color=darkred]
>>> Q wrote:
>>> 93 Pickup 2.4, 211,000 miles, manual trans, 2wd.
>>>
>>> The truck will run fine for hours, then while driving at any speed
>>> it will cut out as if the coil wire were arcing, then back to
>>> running fine. It's not dependent on RPM, speed, or throttle
>>> position although it hasn't happened at idle. It starts well and
>>> runs smoothly. What I've done so far:
>>>
>>> New cap, rotor, wires, plugs.
>>> Ohmed pickup coil in distributor OK
>>> Checked pickup coil air gap. OK
>>> Ohmed high tension coil OK
>>> Replaced high tension coil and ignitor with known good one.
>>> Checked for computer codes. None
>>> Checked timing. OK
>>> Checked connections on coil, distributor, computer.
>>> Adjusted valves.
>>>
>>> Any ideas?
>>>
>>> Q[/color][/color][/color]