I have 1999 ford crown vic. when warm, rpm shoots up at 35 mph and then falls...

B

Bobby

New member
...down followed by engine pinging? I have done of fuel cleaning stuff. four different transmission shops told me that transmission is all fine. I have changed the fuel filter, changed spark plugs, replaced the intake manifold, got new fuel pressure regulator but it stil does that. It happens only when the engine is hot and has run for a while ( particularly on highway). Could it be the oxygen sensor? I have also replaced MAF and TPS sensor.
 
You are wasting a lot of money by replacing all of these parts without knowing what the problem is.

When the RPMs fall, is it just the transmission changing gears? What do you mean by the engine pinging? Is it knock? If your engine is knocking, use a higher octane gasoline. That should solve the problem. Older engines get carbon buildup and can experience pre-detonation (knock).

Quit going to so many transmission shops. Transmission shops are some of the sleaziest businesses out there. If one says nothing is wrong, then he is probably telling you the truth. I'd worry if one told me something was wrong. Those guys are always trying to screw people over.
 
You are wasting a lot of money by replacing all of these parts without knowing what the problem is.

When the RPMs fall, is it just the transmission changing gears? What do you mean by the engine pinging? Is it knock? If your engine is knocking, use a higher octane gasoline. That should solve the problem. Older engines get carbon buildup and can experience pre-detonation (knock).

Quit going to so many transmission shops. Transmission shops are some of the sleaziest businesses out there. If one says nothing is wrong, then he is probably telling you the truth. I'd worry if one told me something was wrong. Those guys are always trying to screw people over.
 
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