My 1992 Ford Ranger hits on all eight plugs when cold but when it gets hot two of each plugs on both coil pac?

(2010-05-30 19:18:11)

1. mudbug Says: when truck gets warmed up two plugs on each coil pack stops firing and truck vibrates bad and won't hardly accelarate. Replaced coil packs, air flow sensor , computer and fuel filter. Every once in a while when it's idling it accelerates by itself. What else can i check?

2. Motorhead Says: First it would be good to narrow down if gas or fuel.
Use an inductive timing light to see if spark cutting out to any cylinder.
If not, then it could be fuel.
And you can usually feel an injector activating with a clicking vibration.

It is it a feedback situation, you could try pulling the oxygen sensor temporarily in order to see if that has any effect.
If so, then it is some sensor or condition that is causing the fuel injection to over compensate.

3. paul67337 Says: just a guess, but it could be the idle air control valve.

4. Petrusclavus Says: Accelerate while idling = free fuel being used for a moment. H.T. lead - chaeck for cracks , the plugs that stop - minute check inch by inch for cracks on the leads to the plugs. Whatever is shorting (it has to be a short by the way) is affected by the engine block getign hot.

5. blakey Says: check engine compression.

6. Ross Says: Throttle position sensor

7. Petey Says: In consideration of what you have already replaced, especially with the fault being tempreture sensitive. I would clearly go directly to the spark module in the distributor. It is probably cracked. Don't be surprised if when you begin to loosen it that it comes apart in pieces. They ae not too expensive, you can get one at a junkyard for next to nothing.