Ford Repair: Ford Explorer 98 trouble, bianchi emilio, oxygen sensors

Question
Hello Dennis, I own a F Explorer 4x4 SOHC 4.0 lts Year 98.
The problem is that the vehicle remains acelerated very often reaching aprox 1500 and 2000 rpm.
When started in the morning, takes aprox 2 minutes on 1000 rpm and after that rpm´s rises suddenly without logic reason.
No check engine light turned on.
I´ve changed IAC valve twice in two yeras and the problem still. Also changed EGR sensor.

Do you think it could be the oxygen sensors?

Thanks inadvance for your help

Emilio Bianchi


Answer
Emilio, just because the CEL is not on doesn't mean there are no codes. You should have the codes checked before replacing any more parts. If then there are none it is a different problem, but a code may lead to the correct repair.

Oxygen sensors have no effect on the idle speed.

There were several campaigns on this engine for your year. One involved the speed control cable, which could  be the cause of a high idle problem. The other involved the intake gaskets and a cam chain tensioner. A intake vacuum leak could also lead to a high or low idle concern, sometimes changing with temperature.

Get the codes read, and check with a Ford dealer about any open campaigns on your vehicle.