Figures, Just as I paypaled a guy on here for some rims, my 1999 vert decided to start to act a fool..Here it goes.....

Car has H/C/I and has been tuned and running flawlessly for over a year. I only drive it about once or twice a month and it sees about 75-120 miles a month (maybe). My primary vehicle needed an a/c compressor so I had to drive this for a couple days to work and around town. I put it away and it needed gas (looked to be just inder 1/8)but it was 3am and I was tired after work. I jumped into it a few days later and it started and ran great. Before I finished backing out of the driveway I glanced down and seen the DIC said reserve fuel (for the 1st time). I drove to the Citgo about 5 blocks away, put 10 gallons of 93 in it then started it up. It started fine and idles like usual. I put it in drive and touched the go pedal and it seemed to be in a limpmode and the engine light was on. I managed to limp it the 5 blocks home and back into the garage.

The next day I put the scanner on it and it seemed to have an old trans solenoid code I fixed but must not have deleted and a 0108 (MAP sensor circuit high input) code. I pulled the plastic covers off the valve covers to look for an obvious issue while it was idling nasty. I noticed the hose on the rear drivers side valve cover was partially on so I pushed it down into the cover and the idle became perfect again. BAM, I thought I fixed it... I sat in the car and gave it some throttle and it has a nasty stumble/hesitation. I tried to let it sit with the battery unhooked to try and clear any old ****, but its still got a nasty hesitation....


Bad gas? MAP sensor needs to be replaced (althought the engine light is not on)?

Any suggests would be great...

 

UPDATE.... I just plugged in the battery and ran the car for a few minutes... Still has a nasty hesitation problem. When I shut it off I had the hood open and I noticed it was making a strange hissing noise which seemed to be coming from the rear of the intake. It was pretty noticable and I'm sure abnormal....

 

Sounds like the vacuum lines at the back of the intake should be checked out.

 

I'm gonna run a little compressed air thru the system now and see what happens. Worst case I have to pull the intake due the the lack space back there.

 

Today I tore the manifold off because I thought I heard a vacuum leak back there. Put it all back together and still acting the same. Its late and the part stores are closed so I'm pretty sure I tested the MAP sensor correctly. Key on Engine Off . Red wire was ground, Gray wire has 5.04 volts, and the green wire had nothing. Test was performed with the MAP plugged in but without a vacuum source. I figured the green wire would be at 5 volts with the KOEO, then drop in voltage as a vacuum source was added. Since I had nothing at the green wire I didn't even break out my gauge to apply vacuum. Does anybody have an idea of what the results indicate? Bad MAP sensor? Break in wire somewhere. harness looked good..

 

Key on engine off w/map sensor plugged in, SHOULD THE MIDDLE GREEN PIN ON THE HARNESS HAVE POWER ? I'm still searching for the answer...

 

TTT, Bought a sensor but work calls so I'll address this issue tomorrow.


After watching a few youtube videos, I've determined that I should have 5 volts at the signal wire with the key on engine off.. I've got nothing..... Looks like it might be an electrical gremlin. I have little patience for this stuff. Time to find a shop.