#1 [url]

Nov 5 09 11:05 AM

I had to put my thinking cap on for this one!

I would place a tachometer on the engine and verify if in fact this is happening exactly when the shift light comes on. As opposed to a certain rpm.

The shift light can come on at different rpms depending on the load on the engine.

If it is just at a certain rpm it will reach, then I would check fuel supply as not being good enough to supply more than a certain amount of fuel. Maybe clogged fuel filter. Maybe pump going out.

If it is in fact when the shift light comes on including lower as well as higher rpms, then I would check the wire coming from the engine computer going to the shift light to be sure it was not shorting to another computer connection. And I suppose a short inside the engine computer could cause this. A short from the shift light output to something else on the computer circuitry board. (Each time the light output comes on, it applies a voltage to something else which keeps the engine from advancing.)