Truck runs like poo

[Burning Splash]

My problem started in December when my mass air flow sensor went bad. I replaced it and the truck ran fine again, but now the truck has similar running patterns as it did when the MAF sensor went out. I pulled the codes and the only code i'm getting continually is 177(O2 sensor bank two reading rich). I've changed the plugs, changed the plug wires, changed the MAF, put new ECT sensor in, and I am still having the problem. After a little while the truck will smooth out and run fine, but then go right back into the problem. It is running so rich that its almost flooding it to death.


The truck is a 94. 4.0 and a 5 speed, no engine mods, just in case anyone needs to know.



Thanks guys,
Burnsey

 

[rustbucketMI]

Check you throttle body sensor

 

[Burning Splash]

i believe that is the only one that i haven't checked..

 

[rustbucketMI]

Try checking that. If that sensor is reading bad then it may be telling you that the throttle is in a position such that more fuel is required.

 

[Burning Splash]

I took the sensor to work with me and checked the TPS and its within specification of what it is supposed to be.

 

['93BajaSport]

Did you check that the fuel pressure regulator is working? How about verify that the O2 sensor on bank 2 is working?

 

[Burning Splash]

Here's what i've checked. Mass air flow, fuel pressure regulator, fuel pressure (key on and engine running), TPS, ECT, IAC, and its still running very very rich.

 

[Masterd]

Stuck injector?

 

[Burning Splash]

Thats my next thought but i can't understand why it would stick only sometimes and follow the RPM range all the way to the top and other times only do it at idle. Any ideas?

 

[Burns]

It quite possibly could be your heavy right foot. You know you have problems with that.

Broke any more trannys lately? Oh that's right there have been none at the house for us to fix in a while. Your thread title is quite funny too.


OK i'm done giving you a hard time.

 

[Masterd]

If you can in fact verify that its running rich (and its not an 02 throwing bad readings) then theres a limited number of things it could be.

Fuel Pump

FRP

Injector

It could possibly be a maf or tps giving the computer bad readings and asking for more fuel, but only one bank is running rich, leading me away from suspecting these.

If your sure that your fuel pressure readings are within spec and the FPR is connected and not ruptured, I'd start looking at injectors.

 

[Burning Splash]

Turns out the Ignition Control Module is going bad. Hopefully that will cure my problem. I couldn't believe how much that stinking thing costs! A new one is $157!!!!!!! Good thing I've got one at home lol.

 

[Burning Splash]

It quite possibly could be your heavy right foot. You know you have problems with that.

You're one to talk little bro lol!

 

[fordnut_1993]

I have the same problem with mine. i think mine might be a leaky injector. It only started to do it since i bought a grand am to drive as a daily beater cause the Ex is expensive to fill. I think the ex is pissed at me for buyin a newer car so its just bein an ass for me. lol

 

['93BajaSport]

Has anyone here actually seen and/or experienced leaking injectors? I really am curious.

For the last 20+ years it generally has been a rare problem for vehicles that get driven regularly. The '86-95 5.0 Mustangs use the same orange-top Bosch 19lb injectors and they almost never fail for any reason at all. That obviously doesn't mean it's impossible, but it would be the last item on my "likely suspects" list.

 

[fordnut_1993]

The thing is tho that it don't burn oil, plugs are brand new and are still clean, all the sensors are near perfect, nothing is jamming up or anything, and it never did it when i drove it regularly. I took it the last couple days and it has been fine. Its just after sitting for a days at a time it does it.