A coil is pretty cheap, try a new one. Just out of curiosity, how did the "mechanic " check the cat?

 

Yeah I'm definitely going to replace it before we pull off the injectors.

And I'm not completely sure if he even did check the cat. My step-dad told me all the things the mechanic checked, the cat being one of 'em. This "mechanic" is a business friend of my step-dad's and he asked him to check out some things on my truck for free <-- which means he could've just said that he tested the cat even if he didn't.

But I've read that a bad cat could/would cause bad smelling exhaust + black smoke + high engine temps + power loss under load/uphill--none of those apply to me, except the bucking + rough idle.

 

If I were you, I would at least unscrew the pre cat o2, take it for a ride and see how it runs.

 

Recently I've noticed my tailpipe is giving out a raw fuel smell--not like sulfur. What could be attributed to that? There is no smoke coming from the exhaust unless it's cold out. (cat + o2's are supposedly in good standing)

Okay so I didn't have anytime to check the injectors so...no news on that.
I'm picking up a new ignition coil tomorrow and putting it in after work so I'll see if that helps any.

I'll see if I can get my mechanic to test the fuel pump for adequate volume since he tested the pressure to be in good standing.

I'll let you peeps know what happens.

 

Throttle position sensor, or Engine Coolant Temp sensor, or IAT sensor, sticking injector(s), bad O2 sensor..... weak ignition..... and probably a few reasons I haven't thought of yet.

 

TPS was already changed...made it even worse.
My truck never overheats and warms up at regular pace + doesn't run/idle nearly as bad cold as it does warm: not the ECT sensor.
My truck has no IAT...maybe your thinking MAP sensor?
I guess the MAP could cause my symptoms...but it's been happening for 6 months and there's no CEL.
Sticking injectors is definitely possible, I'm stilling waiting to check those.
O2 sensors were already changed + cat was checked.

-And my truck has zero problem starting.
-Idles high when cold
-Rough/sometimes low idle when warm.
-While steadily driving + sometimes on acceleration the truck slows/feeling of resistance then proceeds to buck (and a knocking noise under the hood)
-Raw fuel smell at tailpipe
-No overheating

 

IAT sensor is in the intake, passenger side, toward the top, front. It's in there.

What brand O2 sensors?

Injector Leakdown test might also be in order....

 

You're probably right. I just checked on advance auto parts for and IAT sensor and nothing came up so I figured I didn't have one. (I just found it under air temp sensor, sorry)

I have no clue what brand O2 sensors they were. I just know before I bought the truck it didn't pass emissions so they put in O2 sensors. Couldn't tell ya if they were new or used :/

I'll ask if the mechanic will do the injector leakdown too. Thanks.

 

Hint: Mechanics hate it when you try and tell them how to do their job.

The best thing you can do if you take it in somewhere, is explain in as much detail as you can what the truck is doing, when it is doing it, how long it has been doing, and if there are any special circumstances when it does/does not do it. Also, anything that has been done to the truck that they are NOT aware of. (if you had it at some other shop lately......) The more you can tell them, the more easily they can find the problem. Running pig rich, like it sounds like it is.... I wouldn't think that would be too tough for a reasonably well equipped shop to figger out. They may hit ya for a couple hours diagnosis time though. Be prepared for that. I know labor rates are killer these days.

 

Okay so...got a new ignition coil and the truck drives perfectly. Except at idle the needle on the tachometer still moves up and down by an RPM or two consistently. But the sound of the idle is much better and it stays at ~625rpms so that's good.

But I'm still leaking oil into somewhere. It's not leaking onto the ground and it's not being burned. And there's no pooling oil in the TB. So I don't know what the other possibilities are?