Hard Start in 96 454. Please Help, this is a doozy

[brycebba]

OK, I swapped the maf sensor and it was the same. I'm going to swap it back tomorrow. There is one thing that could be related to the maf or could just be the condition worsening, it was doing the same all around but the further I drove it was struggling more to Rev up. It was very slow and took a lot of throttle. When I got back to my house I went back to the tailpipe and the exhaust was really hot. I mean hot enough you wouldn't want to hold your hand 6 inches away and it stinks! It's a hard smell to describe but it's something funky mixed with the smell of a gun right after you have shot it.

Still no codes!

Oil is getting darker naturally but no sign of coolant or gas or anything and the coolant is clear.

This is getting old haha

 

[brycebba]

I forgot to mention that I have had a little exhaust leak for a while and it is definitely getting worse. It's blowing out of the front gasket that has the pipe and cat in it. I'm not sure if that is due to anything I have done.

 

[SAATR]

Sounds like one or both of your cats bit the dust. Super hot exhaust, struggle to rev, and funky smell usually point to dead or collapsed catalyst. Back pressure test would confirm that.

Sent from my XT912 using Tapatalk

 

[brycebba]

I don't have one of those gauges. When those kinds of symptoms occur do you have a guess on the percent of time that it is cats?

 

[98_k1500]

It will run fine without the pipes bolted to the ends of the manifolds. Just unbolt it here, take it for a spin, and see if thats your problem. It don't use the o2s until its up to operating temp anyway. It will just force it to stay in open loop and should run fine if this is where your problem is. It will turn your CEL on if you run it long enough to go into closed loop, but should run flawlessly.

 

[brycebba]

I sprayed wd40 on the nuts and those things wouldn't budge and then broke so I couldn't take them off. I talked to a mechanic shop that I have gone to and they said it sounds so strange that it has had so many various problems including this last thing where it runs like total crap and I never get codes. They suggested before I proceed with cats to put the new pcm in to see if that changes anything or throws codes. Black bear performance shipped my pcm overnight today so I should be able to pop it in tomorrow.

 

[SAATR]

I doubt you'll see a miraculous difference given the issues you've been seeing, but here's to hoping. The gauge is $40 off Amazon, which I personally would gladly pay rather than have to deal with the fun of dropping the Y pipe if it wasn't necessary. Since you've already tried to drop the exhaust and will have to pull it (or have it pulled) to repair the broken/stripped studs, then buying the tool is pointless. It's certainly worth the headache and money on new gaskets though, broken bolts aside.

 

[brycebba]

Yeah I'm not expecting anything really that would fix the problem but more hoping that for whatever reason it will throw codes for some of the problems where mine hasn't at all.

Maybe the flashpaq has effected the pcm in some way

 

[brycebba]

Stupid post office seems to have misplaced the package on the shipper end so I will see if it comes Monday.

 

[brycebba]

OK, got the new pcm in and I can tell that behind it running like crap it will run a lot better. Got a P0174 for bank 1 and 2 sys too lean which I guess is good Cuz I haven't been getting any codes. I ordered 2 cats that will be here tomorrow so I will try those unless anyone has any clues on why the pcm believes it is running lean? What a beast! Luckily I love this truck or I would kick it to the curb

The exhaust leak that I hear seems to sound worse with the new pcm over stock. Could a bad exhaust leak around that flange cause the o2 sensors to read lean or bad cats with too much back pressure?