Glad to see SEAFOAM did the trick for you for a little bit. I've been battling cylinder 3 misfires for a while now. I've got the van in the shop right now getting a new distributor gear. Hopefully that does the trick. My problem is similar, but not as bad as yours. I've got 135k miles on my 04 astro, recent tuneup with plugs, cap, wires. It'll drive around the city like a champ, no misfires, runs great. Only seems to happen when i'm on a road trip, fully loaded with camping gear, going around 55mph it'll start to misfire. I got the SES light to flash a couple times and it gave me the P0303 code.
Newbie AWD Astro Overlander Build
- Thread starter nobodyhome
- Start date
nobodyhome
Adventurer
Well, could be, never hurts to try huh. Although I may have burned up my cat or O2 sensors or something because its been stumbling ever since.
Anyone else have this experience?
UPDATE: Apparently this is a temp fix to isolate the issue and not recommended as a long term solution.
Anyone else have this experience?
UPDATE: Apparently this is a temp fix to isolate the issue and not recommended as a long term solution.
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nobodyhome
Adventurer
The most interesting thing happened today....
Ever since the Seafoam trick, the van was hesitating off the line and loosing power when driving intermittently. My economy went even further into the toilet at ~10MPG. I read somewhere that pulling the battery and grounding the computer overnight would fix it by forcing the computer to completely reset itself. Well guess what, it worked... now the misfire is back. I think I've got a bad computer, maybe a loose wire somewhere. Local dealer has offered 1hr free troubleshoot time, fingers crossed...
Ever since the Seafoam trick, the van was hesitating off the line and loosing power when driving intermittently. My economy went even further into the toilet at ~10MPG. I read somewhere that pulling the battery and grounding the computer overnight would fix it by forcing the computer to completely reset itself. Well guess what, it worked... now the misfire is back. I think I've got a bad computer, maybe a loose wire somewhere. Local dealer has offered 1hr free troubleshoot time, fingers crossed...
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nobodyhome
Adventurer
We've officially named the van;
Na na na na na na na NA
BAT VAAAAN!
Na na na na na na na NA
BAT VAAAAN!
tequilasunset
Adventurer
LOL... nice!
nobodyhome
Adventurer
The verdict is IN....
VALVE JOB FOR THE WIN!
Cyl 1&5 failed leak down at 20% loss on the exhaust valves. $!#%÷×&*! Valve guides.
VALVE JOB FOR THE WIN!
Cyl 1&5 failed leak down at 20% loss on the exhaust valves. $!#%÷×&*! Valve guides.
Mwilliamshs
Explorer
Lapping or machine shop?
nobodyhome
Adventurer
Cylinder head exchange, so the whole enchilada
Mwilliamshs
Explorer
Good call! Since ya gotta buy all the gaskets either way, might as well make all the progress ya can while you're in there!
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nobodyhome
Adventurer
Thank you, I agree. Will do intake gasket, exhaust and inspection along the way. Bottom end is strong, so I feel this is the right way to do it.
nobodyhome
Adventurer
Think I'll paint the heads and valve covers a nice classic Chevy orange, for nostalgia.:sombrero:
nobodyhome
Adventurer
MPG UPDATE:
Well, after everything I've done on the van, it wasn't until I swapped out the knock sensor did my economy finally make a measurable improvement.
At the low point I was getting 10.8MPG. After the knock sensor, I'm back up to 14.1! I'm hoping the valve job will get me back up at least into the 16's.
Mwilliamshs
Explorer
Likely it was detecting false knocks and retarding timing excessively. Good for you on the improvement!
nobodyhome
Adventurer
Agreed, thanks.Talk about improvement... Gassed up yesterday, drove about 70 miles, looked up and saw this on the old nava- computer...
ihatemybike
Explorer
The overhead usually says you burned more fuel than actual, so you are probably doing even better.