Engine running rough and transmission not shifting right

[WELDUR]

My 03 avalanche 5.3 is running horribly and not shifting properly. In the past 2 days I've replaced the cam sensor and crank sensor with it still doing the same thing. I'm not throwing any knock codes. I have almost zero acceleration and it acts like it don't want to shift. When I pull it into first it will either shift out of first or not even go in like it's stuck in 2nd.any ideas? Before I blow it up cause it's angering me? Thanks in advance

 

[ronthehandymanga]

Check the MAF and see if it needs cleaning, CEL?

 

[ygmn]

check fuel pressure too

 

[WELDUR]

Replaced MAF and fuel pressure is good... I'm thinking possibly my exhaust is stopped up. My cousin decided to beat my converters and gut them. I've been fighting this for about 2 months and sank a lot of money thus far

 

[EXT4ME]

... My cousin decided to beat my converters and gut them. ...

So, if he just whacked on them to break up the insides, where did he think the guts were going to end up?

 

[ygmn]

IF he removed cat guts yo would get a check engine light?

are you sure you have power to the OBD port and maybe some stored codes?

normally if it runs crappy like a misfire you get codes

 

[WELDUR]

IF he removed cat guts yo would get a check engine light?

are you sure you have power to the OBD port and maybe some stored codes?

normally if it runs crappy like a misfire you get codes

It's kinda hard to explain exactly what it's doing. Let me hook my modis back up and I'll show yall what it says... Im stumped

 

[WELDUR]

Exhaust is clear fuel filter new sensors replaced... Im about done

 

[CarMech1969]

Ok since you said you have a 5.3 engine, I'm assuming it has a 4L60E transmission.
I have heard of the main harness connector on the transmission getting gunked up with leaking ATF and causing electrical issues.
Would be worth a look to pull that connector out and ensure that the pins are clean and dry, and free of any corrosion. Make sure there are no bent pins either. Other than that, it's anyone's guess - since none of us are there, and we can only go on with whatever info you give us.
You said there is no knock codes.
Were there any other codes?
Perhaps you can show us a picture of what the Modis says.
Didn't you say you would do that?

 

[WELDUR]

Only evap code low circuit and a heater code but yes I will check the transmission harness first thing in the morning and I'll respond back with the findings

 

[WELDUR]

I forgot, now it's having trouble starting right up. Takes a couple key turns now. Fuel pump?

 

[ygmn]

check fuel pressure when running, and with engine off after running to see if it is bleeding off.

 

[EXT4ME]

What "heater code" are you getting?

If it is an O2 sensor heater failure code and your cats are damaged or missing, perhaps these may be part of the issue.

The engine would prefer to have functioning O2 sensors and cats to run properly.

If the O2 sensors and cats are gone, did you do any engine tuning to address that?

Perhaps a smoke test is in order to see if there are any intake leaks.

As mentioned, check fuel pump pressures at key on/engine off, engine on and key off.

My 2003 had an issue where it would take a couple of turns of the key to get it to start and run.

Ended up being the check valve in the fuel pump that was supposed to hold the fuel pressure up after the key was turned off.

The fuel pressure would drop to zero as the key was turned off.

If would take a couple of seconds for the fuel pump to build up to full pressure when the key was turned on.

Once started, the fuel pump would hold good pressure and the engine would run.

Replacing the fuel pump fixed that problem.

My 2003 also is one of those that has a frame mounted fuel filter.

Does yours and have you changed that?

If you do not find a fuel filter on the frame under the driver's door, then your fuel filter is in the fuel tank and is part of the fuel pump.

 

[WELDUR]

sorry everyone been really busy, but i finally checked the fuel pressure tonight and running its only like 31 PSI all other codes other than EVAP have been resolved but occasionally I'm throwing a misfire code and per my MODUS its saying its throwing on cylinders 2,4,5,6,7,8. im thinking fuel pump now. ugh

 

[ygmn]

Fuel pressure low.
Check regulator and pump.