CEL and bucking problem

[Louieisawsome]

Ok, so I have some codes on my 1990 EFI auto and I've tried a bunch of stuff to fix this.
Basically the engine runs great idles great, just bucks (misfires?) under heavy acceleration until I let off the gas, gets pretty violent if I keep my foot down lol.
Usually in 1st gear but it's happened in 2nd gear.
Used to be a intermittent but now it's constant.

Codes:
Flashes code 09 (coolant sensor) at first but then doesn't repeat it.


02 CPS (replaced disty no effect)
15 o2 sensor
17 o2 sensor (replaced no effect)

Also replaced fuel filter and cleaned/tested injectors. Newer fuel tank and pump.
Spark plugs look good. Timing good.

Out of ideas. Any help is appreciated!

[FestYboy]

Look for holes or cracks in the intake tube (rubber part), and carbon tracks on anything between the coil and spark plugs (you can also test for spark leak with a spritzer bottle of water).

[WmWatt]

Does it buck at idle when you increase engine speed by pulling on the throttle cable in the engine compartment? I'd start by cleaning the ignition components, wipe clean with a rag, and maybe squeeze the connectors on the ends of the ignition wires a bit for better contact. Look inside the "tower" connectors on the coil and distributor cap for dirt, moisture, and corrosion. Before pulling the rubber caps back to expose the ends of the igntion wires I give them a shot of WD-40 so they will slide on the wire insulation. If you have a vaccum guage it will show missing as vibrating of the needle. There is info on vacuum dianosing an engine at the top of the repair forum page.

[Louieisawsome]

OK new wires and plugs, no difference. Gassing it in park doesn't cause the stumble.

[FestYboy]

OK start with diagnosis, then replace parts and THEN do maintenance items.

[firebush357]

Have you checked your Transmission Fluid by any chance? I'm just taking a wild guess and thinking maybe it isn't mis firing but slipping in and out of gear?

[Louieisawsome]

Transmission fluid is good. I believe the problem is worsened by spraying water in the engine bay and super heavy rain.

[bolokid]

You mentioned that you changed the distributor, did you also change out the distributor cap?

[Louieisawsome]

Yeah, I threw a whole other one in. Cap rotor and all cleaned it too.

[Fecomatter]

small engine bay fire will clear up moisture

[bravekozak]

I just plug in my engine block heater.

[Shin Hayata]

I just plug in my engine block heater.

I found two on the bay. Similar, but seemingly not identical.

<First one>
<Second one>

Which one do you have? Where is the heater plug installed on the block?

I was thinking about a magnetic heater (click), but I do like the integrated fit of what you used, bk.

[WmWatt]

Block heaters were factory installed on vehicles sold in Canada. I use mine for about 2 hrs before starting on cold days. In the far north fires are sometime lit under engines before starting in very cold weather. An electric heater under the engine bay should dry out the engine where electric power isn't expensive.

[bravekozak]

The part number was in the file name of the picture.
E8GZ-6D008-A
GZ denotes a Mercury Tracer.
There are quite a few of them at Rear Counter.
But, they are probably a lot cheaper on the bay.
The installation instructions tell you which plug on the rear of the engine to knock out, as well as the direction to orient the resistor.