Misfire That Fixes Itself For A Little Sometimes


New Member
May 25, 2017
I need some help here. I just bought a used 99 v6 not too long ago and while driving in the rain the other day is started to hiccup and misfire. It has a CAI and the air filter is open to splashing from the wheel as there is no wheel well cover. Its been a few days since then and I'm getting a mostly reliable misfire on cylinder #2 (? i think) that fixes itself sometimes but then starts happening again. Does anyone have any ideas? The check engine codes are listed below

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SN Certified Technician
Aug 14, 2009
Houston Texas
Yes. Water in the MAF.

Seriously. That's a ton of DTC codes. The book says to focus first on the misfire DTC's. However I believe that any "Circuit Malfunction" DTC should also be reviewed.

>>From Ford manual
P1100 - Mass Air Flow (MAF) Sensor Intermittent
P0443 - EVAP Control System Canister Purge Valve Circuit Malfunction
P0455 - EVAP Control System Leak Detected (No Purge Flow or Large Leak)
P1451 - EVAP Control System Canister Vent Solenoid Circuit Malfunction
P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
P0141 - HO2S Sensor Circuit Malfunction (HO2S-12)
P0155 - HO2S Sensor Circuit Malfunction (HO2S-21)
P0161 - HO2S Sensor Circuit Malfunction (HO2S-22)
P1409 - EGR Vacuum Regulator Solenoid Circuit Malfunction

What is a "Circuit Malfunction"? That is something sooooooo wrong with a circuit that the PCM isn't able to perform any diagnosis. Think, no power, bad wring, disconnected sensor, short, ground fault.

I'm also a big believer in Occam's razor.

Anytime one is dealing with so many big DTC's a single common simple fault should be considered.

What ONE thing do all of the above sensors have in common? Drum roll......... Wait for it. This is good...... You will like it I promise. >:)

Fuse F2.8

1999-2004 MY fuse panel schedule:

Start over with the DTC's that are left. Could be down to just the misfire DTC. Note, it's quite possible that water in the MAF is what caused the fuse to blow.

Here's some information on an ODB2 tool that may make a big difference in your trouble shooting.

ForScan ODB2 scanner w ELM327 USB

Having a Ford Factory service manual with wiring diagram can also be a huge help when trying to get a "new to you" car back on the road again. If interested in getting a set for yourself I maybe able to help. PM if interested.

I always recommend starting every trouble shooting session with a through review of the battery and charging system. Here's some information that might help.

Howto perform charging system voltage drop test

Copy/past of reply given in other thread:


SN Certified Technician
Aug 14, 2009
Houston Texas
To the OP. There are other people reading these threads. These threads have more value when they are updated with the "lessons learned" about the problem at hand. Your experience may help someone else solve the same or a similar problem.

Not to mention that it's not really polite to ask for help and be given good solid help with tons of detail and not at least acknowledge it.

The forums work best when everyone contributes. Are you going to do your part?
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