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Ford Explorer Community - Maintenance - Modifications - Performance Upgrades - Problem Solving - Off-Road - Street
Explorer Forum Covers the Explorer ST, Explorer Sport, Explorer Sport Trac, Lincoln Aviator, Mercury Mountaineer, Mazda Navajo, Ford Ranger, Mazda Pickups, and the Ford Aerostar
HI All, I have read a few threads on these codes. Background 98 4.0L, 2wd. I suspect a bad wiring at the MAF. REason is the BARO pid keeps setting back 4000ft elevation and I am sea level. The MAF has been replaced. No driveablity problem. Runs smooth lots of power. No obvious vacuum leak. Fauly code trigger show Longft at 8% and shrtft at 10%. I was a ford tech for about 15 years and seem to remeber a MAF connecter recall or tsb. Anyone remember this at all. Thanks for any input.
Since you obviously have a scanner I suggest that you read the MAF sensor airflow in pounds per minute to see if it looks reasonable. Your long and short term fuel trims support the lean condition DTCs. Do you have the SOHC V6? If so, you probably have leaking manifold gaskets.
HI All, I have read a few threads on these codes. Background 98 4.0L, 2wd. I suspect a bad wiring at the MAF. REason is the BARO pid keeps setting back 4000ft elevation and I am sea level. The MAF has been replaced. No driveablity problem. Runs smooth lots of power. No obvious vacuum leak. Fauly code trigger show Longft at 8% and shrtft at 10%. I was a ford tech for about 15 years and seem to remeber a MAF connecter recall or tsb. Anyone remember this at all. Thanks for any input.
95-96 is ohv only.
Does IAT=ECT at startup? This is also used to compute baro.
Check all vac hoses for leaks, maybe even isolate them to be sure.
Check DPFE_V , should be .5 or 1 at idle. (check for egr leaks)
Do a step (goose throttle) response test on the MAF, see if you get a nice peak curve.
Could be upper intake gaskets, but there is usually drive ability symptoms if that is the case. What is the fuel trim after its warmed up?
Here is some more info to replies of this posting. Ect and iat read within 4 degrees of eachother dead cold. ect 40 and iat 46 first thing in am. need to check dpfe. MAF was replaced already. o2's both replaced previously by someone else. I checked and they both look new. fuel press and leak down checks all pass per ford pced manual. that included fuel press reg check. no obvious vac line cracked that can be seen. There only a few vac lines that I can see, you know they are covered with protecter covering. Manual check egr seems ok and remeber the dpfe are notorious for failing but usually set a code.
I plann to repair damaged wiring at maf connector clear kam and see what happens. will also chek other items as suggested here.
This is a friends truck and is a definetly a 98 4.0L
Sometimes the EGR can hang open a bit at idle, not give a code but will show up on the DPFE (when its working properly) as a slightly higher voltage. I had this problem. It will also trigger lean codes. Not common, but something to think about.
If its the SOHC the intake gaskets could be just starting to go bad.
