Running rich and stumbling

Hello so recently I’ve been noticing some issues that have shown up. For a back story my fuel pump went out a few months ago got it replaced and was good. I did have a po172 show up but hasn’t came back yet. Currently sometimes when I start the truck up in the morning the idle will be some what low or regular. But once I put it in reverse it wants to stumble or die almost like it could be flooding with gas? I do smell it so it’s not running lean. My fuel trims are showing rich signs as well. Any help or ideas would be appreciated!

 

Bump

 

Kinda sounds like idle air control to me, but I did just have a margarita.

 

I’m noticing my idle as well is higher then normal

 

My second guess would be a fuel pressure regulator, especially with the negative fuel trims.

 

It comes at goes tho like sometimes fine sometimes positive or negative

 

I had an 97 2.4 that did that and when it was acting up the a/c would not blow cold. Then it would be ok for a few miles then again. It wound up being the computer under dash and above the shifter , oh it was a five speed manual.

 

It’s weird it’s like a on and off thing sometimes it’s fine somethings it’s not makes me feel like a wire issue possibly. Or maybe the iac valve on the throttle body

 

I know, some days is was fine and then all of a sudden it would stumble, loose power, a/c would not blow cold, then it would clear up a/c blows cold all ok for a bit

 

Wanted to bump this im still having an issue. Long term fuel trims go from -20 to -7 so without throttle is -20,-18 but when throttling long term is around -7 or close to 0. Could really use some help. Only thing I know so far is that I had the fuel pump replaced back in December but haven’t had a problem for a little it would sort of stumble at idle and I’m getting a smell of gas fumes sitting in the cab.

 

Any engine codes?

Rich fuel mixture added with a high idle sounds like an ECT sensor issue preventing it from getting out of open loop.

 

So I had a po135 I think it was bank 1 oxygen sensor. I replaced it cleared code and good. I had a po172 running rich code but I cleared it and hasn’t shown up again. Yet my long term fuel trims are -15,20 at some points and even my short term can get up to 15 plus sometimes. My ECT sensor was replaced and is working I use a ultra gauge and it reads normal. It doesn’t idle high anymore it seems

edit: I also have a exhaust leak it sounds like from up close to the header could be a flange but I’m not sure if that would run rich

 

Do you have a way to check your maf rate through the whole range....

Same for the throttle position sensor.....do you have a way to check for smooth operation...

Same for egr valve .....when mine switches on or off ....the fuel trims shift wildly......like +10 to 15 difference when its open...
should be off at idle....and full on when accelerating .......


May not be able to see all this unless using one of the more capable scanners.

 

I mean throttle sensor looks to be fine? It gives me a percentage so 12.5 idle then throttle goes up as I press the gas

 

I've always wondered how to defeat....to shut egr valve by force...

would all I have to do is block off the vacuum line going to it?

and if so what does that do to the ecm's closed loop......


keep in mind....this a good way to overheat your engine.

 

What running rich is a possible way for overheat? It’s hard to tell cause I had a the fuel pump replaced so I’m still thinking to check the fuel pressure

 

Your engine is running way too rich......
its like your injectors are running jumbo size....

the ecm tries to correct it at the O2 sensor.....

by cutting way back on your fuel being delivered...

like you said.....like its getting flooded for the volume clean air its has....


An after market maf or dirty maf sensor would be my first guess...


JOB 0 would be check all battery and grounds thru out the whole vehicle....

Next in line would be a bad sensor somewhere.....these ecm's dont like non oem stuff....

 

Yea my sensors are oem so it’s confusing. It’s hard cause it has a slight rough idle sometimes then sometimes not. Then I can smell fumes of gas while running could be the exhaust leak tho

 

My fuel trims with cold air induction run a little rich at idle....maybe -2 or -3.

When the egr kicks in under load.....it shoots up to about +7 to +9.....

 

Yea I mean that’s fine tho im seeing 12-15 or even 20 at times negative that’s not good assuming 10 percent is like the median lol.