'90 4.3 running rough

[Rob_277]

She's a 90 Sierra Stepside with a 4.3 TBI under the hood. The truck has been running great for 245,000 miles on it. Other than a little popping due to a cat delete and a dynomax muffler giving virtually no back pressure. Today i had to make a quick turn off the road to avoid getting slammed by an 18 wheeler. the road i turned onto has a decent drop to it and i hit it doing atleast 40 or 50 after that she ran rough and started some harsh backfiring. i pulled over and inspected the engine bay and found the PCV out of the head cover and the vaccum hose servicing the EGR loose, and bracket connecting one of the sensors to the bottom of the throttle body broken. She stumbles like a bad vaccum leak on start up but eventually plains out after a few minutes of touching on the throttle. I ran a snap-on OBD reader on it and it brought up a code 32 &33. which is an EGR problem and a high MAP sensor reading. I checked the MAP sensor reading and at idle it's showing 4.86 which is extremely high considering it should be about 1.00. I'm i guess you could call an amateur mechanic. I don't know everything but i can hold my own with working on cars. I wanted to see if anybody more familiar with the truck could give me any suggestions on what to do so that i'm not wasting my time. Thanks.

[Rob_277]

Ok 1 smiley can sum this up...

 

Uppon further inspection, i took the filter housing to get a better look. I though all the vaccum lines were connected but i looked a little closer and sure enough the line to the map sensor was indeed unhooked. i believe this would explain the map sensor reading of 4.86 v. i hpoe that was causing the EGR screw up too. now on to my original intentions of scrubbing down the throttle body. it appears to have a layer of crud in it atleast 1/2" thick.