GM '05 Astro Van with intermittent missing (1 Viewer)

[meatloaf]

'05 Astro Cargo van, 125K miles,

I bought this van for work and it has been nothing but a nightmare after another...bought at an auction from a school district near Dallas. Drove it home to Austin and other than AC compressor clutch locking up, it ran fine, Installed new AC compressor and new radiator, tstat, hoses, belts & fan clutch since the radiator started leaking... Also, installed new brakes/rotors on all 4 corners along with rear calipers.

Looked at the Chevy Astro forums for insight to resolve issue(s) below and still haven't been able to fix,

latest symptoms is that it runs ok and then it misses then runs fine for while then it misses again, sometimes worse than others. sometimes check engine/service engine lights come on and off quickly, sometimes they don't. Initially I had no codes while it was doing this until it started missing constantly, it gave me a cylinder 5 misfire. I replaced rotor, cap, spark plugs & wires. Ran fine for a while and it started again. I took it to a mechanic in Houston and he changed the coil pack, fuel/air filters, transmission fluid/filter. 10 miles later it started to miss again on the freeway. When I got home to Austin, I replaced distributor with a new one, no change. replaced fuel pump, no change. Sometimes the abs and brake lights come on while driving and stay on until I turn the van off.

Could it be a wire or the harness? injector(s)? MAF? or the computer?

Thanks.
ML

 

[BILT4ME]

'05 Astro Cargo van, 125K miles,

I bought this van for work and it has been nothing but a nightmare after another...bought at an auction from a school district near Dallas. Drove it home to Austin and other than AC compressor clutch locking up, it ran fine, Installed new AC compressor and new radiator, tstat, hoses, belts & fan clutch since the radiator started leaking... Also, installed new brakes/rotors on all 4 corners along with rear calipers.

Looked at the Chevy Astro forums for insight to resolve issue(s) below and still haven't been able to fix,

latest symptoms is that it runs ok and then it misses then runs fine for while then it misses again, sometimes worse than others. sometimes check engine/service engine lights come on and off quickly, sometimes they don't. Initially I had no codes while it was doing this until it started missing constantly, it gave me a cylinder 5 misfire. I replaced rotor, cap, spark plugs & wires. Ran fine for a while and it started again. I took it to a mechanic in Houston and he changed the coil pack, fuel/air filters, transmission fluid/filter. 10 miles later it started to miss again on the freeway. When I got home to Austin, I replaced distributor with a new one, no change. replaced fuel pump, no change. Sometimes the abs and brake lights come on while driving and stay on until I turn the van off.

Could it be a wire or the harness? injector(s)? MAF? or the computer?

Thanks.
ML

I'm guessing you have a damaged wiring harness somewhere.

I had a 98 Chrysler T&C that I replaced a thermocouple that controlled the cooling fans. I replaced that t-couple 5 times. Then I started having issues with every time I revved over 3000 RPM, the lights got really bright, then would blow out the headlights. Replaced the alternator twice.

The regulator for those is built into the computer, not the alternator.

I eventually took it to a dealer because I was so frustrated. They found a bad harness under the front of the van (no visible damage), and $175 later, I was back with no issues.

That was one of the few times I've taken a vehicle to someone else. They still only installed half of the bolts and screws to put it all back together (yes, that's what they did...separate bitch session) In the long run it was definitely worthwhile.

 

[meatloaf]

Thanks @BILT4ME , I need to look into the harness, can’t really remember but I believe the problem started after I removed parts to replace AC compressor. It’s just really frustrating to the point that I want to sell it

 

[BILT4ME]

Thanks @BILT4ME , I need to look into the harness, can’t really remember but I believe the problem started after I removed parts to replace AC compressor. It’s just really frustrating to the point that I want to sell it

Are you losing any coolant?

 

[meatloaf]

Are you losing any coolant?

Not that I know of, I assume no since all cooling components (water pump, tstat, radiator, hoses,fab clutch, coolant) were changed about 2 months ago. I did notice that there was rust when I pulled off the radiator cap which seemed strange to me

 

[BILT4ME]

Not that I know of, I assume no since all cooling components (water pump, tstat, radiator, hoses,fab clutch, coolant) were changed about 2 months ago. I did notice that there was rust when I pulled off the radiator cap which seemed strange to me

Misfire on a cylinder could be electrical or fuel. Could be a bad injector(s).

Fuel pump old and weak? Do a fuel pressure test?

 

[meatloaf]

Misfire on a cylinder could be electrical or fuel. Could be a bad injector(s).

Fuel pump old and weak? Do a fuel pressure test?

fuel pump replaced 3 days ago.

what I don't get is that the misfires are intermittent, wouldn't a bad injector cause constant misfire?

 

[BILT4ME]

fuel pump replaced 3 days ago.

what I don't get is that the misfires are intermittent, wouldn't a bad injector cause constant misfire?

Not necessarily. It could be sticky. Or a bad ground wire or bad plug connection on the injector.

Do you have a cracked spark plug? They can be finicky sometimes.

During install, a tweak on the plug may crack it and it may affected by humidity of the day.