1997 Ford Expedition Q&A
1997 Ford Expedition Question: engine runs rough at 1500 rpm.
when you idle the engine at 1500 rpm the idle goes up and down. when you drive at 1500 rpm the engine stumbles and misses, with a dead spot. i have replaced the following- EGR valve,EGR pressure sensor,hoses,fuel pressure regulator,spark plugs,coil packs,pcv valve,cleaned the throtel body,replaced air filter.before i did this their was a code P0401,no code now.and before i replaced all these parts, the problem would come and go. now its always their.i used to be a chevy man,im trying to expand. signed heavy chevy. - Visitor
idle air sensor is bad - Visitor
It sounds similar to an exhaust restriction.put a vacuum gauge on a vacuum line and rap the throttle while in park.the vacuum should snap back to what it was at idle.if it moves slowly to the reading at idle you have a restriction.also the baro pid is a telltale sign(if you have a scan tool available)anything in the 149hz and below is also an indicator.or if you have access to a backpressure gauge,should not read above 3psi.good luck! - bmdouble