Maybe that's the problem, no 02 sensor..?

 

OK, so I took the throttle body off, cleaned the IAC and the throttle body up really good and put it all back together. Fired right up and ran good, but I'm getting a code for map sensor. It came up once before a few months ago, but didn't cause any adverse effects. Could that cause my bogging/ stumbling issue?

 

I would say probably not, only from experience of getting a map code on my old truck and replacing it did nothing to help performance problems I was having at the time. Have you had backpressure checked? Do you have a vacuum gauge to see how well engine is breathing? Just some ideas, but the map code is probably a result of what the real problem is and not the problem itself. A bad 02 will cause bogging and stumbling.

 

I don't have a vacuum gauge to check that stuff, but I'm gonna buy one now. I've driven that thing without an o2 sensor for 6 or more months, why would it go mental now??

 

the front o2 sensor is used for maintaining the air fuel mixture at stoichiometric 14.7:1 with out the o2 sensor your truck will stay running in open loop which is pig rich to help with staring and warm up. running to rich can cause your cat to plug and harm the cylinders and valves. chances are the front o2 sensor being out is what started and or contributed to the problem. the map sensor is used to with rpm and throttle position to determine engine load so the compuer can make fuel adjustments. a bad map can cause lack of power under load and other drivability problems.

 

I guess that would contribute to me averaging 9.5 mpg. I'll go to the exhaust shop this week and bet an o2 bung welded in and see what kind of difference that makes. Getting a cat is gonna have to wait for more funds...

 

Check the little elbow hose that goes from the TB to the MAP. If it is dry rotted, and leaking, you will continue to get map codes, and the engine will run phuny.