Everybody here says the Bosch sensors are crap in our our trucks. Take a can of starting fluid and carefully spray it where you think you might have the vacuum leak. When it revs up you found your leak.

 

I would rather use something non-combustible, and listen for the engine to idle down..... less fire hazard that way.

 

What else will work? I've always used starting fluid.

 

i used carb cleaner today to try to find a vacuum leak, didn't find anything.. i think maybe i have bad fuel injectors.. or is it a possibility that my engine is a 318? i used my intake manifold and injectors from my old 360, if the engine in there now is a 318 then could it be injecting too much fuel because of the 360 injectors? the guy i bought it from said it was a 360 but you never know.. it was a used engine. how can i tell the difference?

 

Intake manifold is the same between the engines (so long as it is from around the same year... 94-96 are different than 97-01).

The injectors for the 360 are a higher psi (I think), but that would lead to more power and not much else...

How did you determine that it sucks more air when it runs rough?

New thought: Its possible that your MAP sensor may be the culprit.

There should be a stamp on the block with a code that relates to engine info, I cant for the life of me remember where though.

Here is a link that tells you how to identify what engine you have via the casting number:http://www.ehow.com/how_7706969_iden...m-engine.html#

 

You need to make sure your O2 sensors are working as they should before anything else happens. You can troubleshoot till the cows come home, but, as long as you are setting O2 codes, nothing you do will matter.

 

The 360s and 318s after 1996 have the same PSI. When they went to OBD II, they also went to a "standard calibration" for the 5.2L and 5.9L V8 injectors.

As for those sensors... either you got two bad units out of the box, which would be very rare and unlucky but not impossible with Bosch "quality", or something else far more difficult. My next guess would be wiring between the sensors and the PCM.

Did you check the fuses in the PDC for the oxygen sensors, make sure they aren't blown? Should be one fuse for each sensor.

 

The engine size is stamped on the block on the drivers side halfway up the block. It's the last couple numbers.

 

Also I've never had carb cleaner work trying to find a vaccum leak. It takes far more to choke the motor down than it does to idle it up. With starting fluid it takes a very small mist and it'll rev right up. Ive never had a problem. If your worried grab a fire extinguisher.

 

yea i think i might try to find a vacuum leak with some starting fluid before i dig any deeper.. but the wires from the o2 sensors to the pcm could very well be the problem. my rear sensor that was on there before was damaged at the top from when i was banging my floors into shape , and the bare wires were hitting the bottom of the floor shorting it out. i dented the floor up so there was no clearance issues when i installed the new sensor. i know that it starts sucking in more air when it's idoling rough because the air filter starts hissing wayyy louder than normal, and if i put my hand over the hole it almost sucks my hand into the airbox, where normally it has a lot less sucktion (sp?) so maybe a bad map sensor? how can i test that? i really hope i don't have bad fuel injectors, because those are $45 EACH! thanks everyone, you've all been very helpful!