Got a code today that i posted about. So I replaced the sensor. Now i don't get a service engine light, but the truck is running like ****. I can hear kind of like a popping and stumpling under light acceleration. If i rev the motor while in park, It sounds like it's breaking up and the rpm fall down to like 400 when i let off and sounds like it's struggling. At the same time, my a/f goes to like 18 and stays there. As the engine smooths out.......the guage comes back up to like 14-15. It feels similar to when my coil pack went out a couple years back but it's wierd that the ses light went off because of the o2 sensor.

Any ideas. So far from what I've come up with......could be Iac valve, (just cleaned in spring), fuel pump (fuel pressure guage shows now drops in pressure even at higher rpm), coil pack, and an exhaust leak may have led to the code i threw earlier, which was po153.

 

clean IAC again.
chagne fuel filter.
Clean MAF sensor.

report back with results

 

i'm gonna start first thing in the morning. It was dark by the time i got home tonight. What is the exact function of the IAC valve?? How would it affect acceleration??

Up over 2k rpms it seems fine, but under there it's bogging, spitting and farting. Sucks when they are broke.

I have a couple good ford dealer i know people who work in the service dept personally. If they road tested it with the computer hooked it, should tell them what's going on right???

 

the iac lets in air around the tb so the engine can still breath when the throttle is still closed

 

Doubt its the IAC, a bad one normally shows at idle.

If it was me, I would change the fuel filter first (easiest) and then go after the coil packs

 

Could you have cooked a Plug tallimeca ?

Hope it's something simple and fixed Lightning quick

 

fuel filer was changed about 400 miles ago, could it have got clogged that fast???

I don't think it's a plug because everything was fine, It sat for 3 days and when i started it and drove it is when i noticed it. It's really frustrating. I'm gonna work on it this morning. All else fails it's going to ford. Will having a chip screw up any ford diagnostic equipment???

 

Yes having the chip in will screw up Fords diagnostics, The SVT Mech at my Dealer said to make sure you remove it before bringing it in as it changes the settings and plays heck with thier readings.

GOOD LUCK, hope it's something easy

 

cleaned iac valve, cleaned maf. Pulled coil pack plugs one by one, all seem to be runctioning, whether they are breaking up at higher rpm, i don't know.

Found out Bank 2 is the drivers side and i changed the wrong sensor, so i swapped them. No codes now but runs just the same.

Checked all vaccuum lines i could see.........nothing.

Called the dealer, I give up and I lost my patience at this point.

Think a leaking header gasket could cause these symptoms. We checked the collector gaskets and couldn't find anything.

 

Did you try resetting your chip! Might not be making good contact, also might want to check the vacum unit by the brake booster. Looking for a vacun leak works best using a small amount of carb spray, if there is a leak it will find it by raising the the idle. Just a couple of quick checks might help! Artie

 

tallimeca, did you check the plugs?? with that high A/F the electrodes might be missing ...........I would keep looking at the coil packs, I have seen the coils check good only to find out there was a tear in the boot ......inspect for tears in the boots.


Any chance you have bad gas...?

 

I had almost no electrodes on my stock plugs when we changed them out...my truck was/is running pretty lean. I never had any symptoms like that though...at least not a popping sound or rough idle.

just a thought...

If you havent taken your chip out then try it... make sure to reset your stock computer before starting it again. Leave your battery disconnected for 5 or 10 minutes...I cant remember how long it takes to clear..but 10 minutes should cover it.

May seem too easy but you never know...the popping sound is kinda scarey though good luck

 

check the connection from the intake to the TB. The plastic boot thing. Mine came off 2 days ago and caused the truck to do the same exact thing. Overlooked it for like 10 mins until some genious ASE certified mechanic found it and charged me for 2 hours of labor. same popping....horrible start off then quickly regained itself. Worth a shot

 

As was mention...bad gas. I see you have checked a number of things.
Even though it was only 400 miles ago, 1 bad tank of gas can screw-up/clog your filter. And for only 10 bucks and some time..............well you know what Iam getting at

 

Bruce,

I limped the the gas startion friday night and filled it half way. I'm gonna change the damn fuel filter anyway tonight if it stops raining. I'm also going to swap Maf sensors because the symptoms point to it being a problem. I cleaned it with no luck. I'll post the results because these situations can always be helpfull to everyone in case it happens to you. If all else fails, i'm tying to get it to ford tuesday.

***why do i still think it's coil packs???? ***