Posted about a week ago about my car sounding like it was starting on 2 cylinders and stalling.

Well now I notice from the safc that when I start the car the pressure reading is -100 mm/hg when usually its like -250 to -350 at idle after a startup. But with the -100mm/hg after like 5 minutes or so of rough idle it goes back up to normal (-250 to -350)??

Any ideas, I was thinking vacuum leak from the TB or something but I just changed the gasket/vc gasket.

But I would thought the bad vacuum would stay even after its warmed up but it fixes itself after like 5 minutes and runs like a champ??

any ideas???

Should I do a compression test?? maybe my HG is leaking?? could that be a cause??

1998 dodge avenger 4 cyl AT
Mods are:
Not enough

anyone??? come on guys give it a try !!

1998 dodge avenger 4 cyl AT
Mods are:
Not enough

I would check your fuel trims by datalogging. I do know that if there is too much fuel during idle it will run REALLY rough, blow black smoke out the exhaust, vacuum of 10 rather than 18 like it should be. When the water temp reaches approx. 120 degrees, the short term fuel trims start pulling fuel up to 25%. So the problem goes away and all is well.

Maybe your AFC is not pulling the fuel it should at idle and this is what is happening. I am not sure about settings on the AFC(do not have one), but if they are all correct then maybe the AFC is malfunctioning.

Basically your car sounds like it is trying to idle 30LB(slightly larger because of the problems) injectors at stock idle fuel pressure without an AFC. Too much fuel and then when the trims max out it idles fine.

When you datalog, see what rpm it takes to get short term fuel trim to be lower than 25%. If it takes 2-3K rpm, then you are exceeding your ecu fuel trimming capabilities(short/long term)at idle.

Just a guess and you said you wanted feedback.

****Try this*****

Start your car first thing in the morning(cold weather). When it is idling really funky, step on the gas and see if you can get it to flood and make the engine die. Never turn the key off, just restart it from the position it is in. If you turn it off and then restart it, you will have the same problem. If when you restart it, the problem goes away. You have too much fuel like I stated above. I have done this a couple times in the past with larger injectors. The ecu will pull fuel because it flooded and quit. When you restart, the ecu will automatically max out the fuel trims to keep the engine running. The car will drive fine and act normally. I have not datalogged this exact problem, but have done this fix many times on my car. It works. I am not sure if I datalogged it, that it would show a max STFT/LTFT of 25% each. Maybe something else causes it to pull fuel and not the trims, but not likely. Just more ideas.

97 RS(PTE SC-61, Built Long Block, Electromotive Tec 3)It's Here!

Do you get any CEL's?? I know i have had a stumbling problem sometimes when cold, from my EVAP system. There is a little vacume solenoid of some sorts up by the gas tank. The vac line on top of the TB leads to this from the EVAP solenoid by the front pass fender. The little rubber diaphram inside that piece by the gas tank can get tares in it, and can cause a small vac leak when the EVAP system is active, which is usually when its been sitting and the motor is cold. Double check all vac lines of course. What are your fuel pressures? Maybe check that too. Just a few thoughts..

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)