Kind of hard to describe whats going on, so please bear with me.

About a week ago, I started the truck, and it would not run unless i put constant pressure on the gas pedal. It ran perfect a few hours before this. I figured the idle air valve was the problem. As I removed the throttle body, i noticed oil pooling in the intake again, so i went ahead and replaced the gaskets. (already did the repair with the kit from hughes engines). Got done with that, replaced the valve, and it idled really high.

I figured i got a defective part, and swapped it out under warranty. Put the new one in, and it's acting even more strange than before.

Sometimes it idles/drives perfectly fine. Other times, it idles at really low rpms. When it does this, if i hold it at 2000rpms for a few seconds, the problem seems to correct itself, and it runs fine again.

So today it didn't want to idle again. So i held it at 2000, and it ran fine, until several miles and stop lights later. It began idling fine, then it suddenly began running rough and trying to stall. Not missing on a cylinder rough, just rough, if you know what i mean. The rpms didn't change, just began running rough.

It was weird because it went from running perfectly fine, to running rough instantly. I didn't hit the gas, didn't move at all.

I'm now wondering if i have a fuel issue, or if i f***ed something up doing the intake gaskets. Everything looks fine. Doesn't mean it is.

I don't know what im missing. Any suggestions at all would be helpful. And thanks in advance.

 

IAC is a good starting poiint as well as TPS. Maybe a vacuum leak. Can you check it? WHy did plenum blow with Hughes plate on there? Were bolts loose?

 

Did you replace the o2 and check the cat?

 

The plenum started leaking because of my stupidity. Didn't have a torque wrench, decided to do it without. Used a torque wrench this time, and followed the torque pattern.

I had not thought about the o2 sensor/cat. And no, i didnt replace them. Any good ways of checking those? I'll probably just gut the cat anyway, Michigan doesn't have emission testing.

Do these trucks have a fuel pressure regulator that could cause this problem?

Thanks for the quick replies.

 

Fuel pressure regulator is on top of the tank. It IS serviceable without having to replace the whole pump/sending unit.

Try disconnecting the O2 sensor, and drive it for a while. (yes, it will indeed set a code) If doing so makes it run better, replace the sensor.

 

...and the cat....

 

if you haven't replaced the TPS yet, i'd do that. the iac and tps are all inter-related.

 

Inter-related.
Is that kinda like marrying your cousin? LOL

 

yes, marrying your cousin is what we do in Georgia.
marrying your sister is what they do in Alabama.

that reminds me of a good joke. what do you call a girl in West Virginia that can outrun her brothers........... a virgin.

here's another. if a couple get a divorce in Alabama, are they still considered brother and sister?

lol.

 

lmfao, thats pretty funny. I will try the o2 sensor thing tomorrow, and replace the tps asap. Thanks for all the help. You guys are great.