2001 Montana 3.4 hard to start and runs rough

robert1292
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Joined: Sun Jan 06, 2013 12:17 pm

2001 Montana 3.4 hard to start and runs rough

Unread post by robert1292 » Sun Jan 06, 2013 12:21 pm

Hello I have a 01 pontiac montana 3.4, when it is very cold outside it is very hard to start it will turn over but it is very rough. also when I am driving slow or at idle it is running rough and studders and wants to stall but when I am at the speeds of 60-80 or higher it is fine.

any answers to what could be the problem??


thanks

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ProTech
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Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by ProTech » Sun Jan 06, 2013 9:47 pm

Sounds like you probably have a misfire on one or more cylinders. This can be caused by faulty spark plugs or ignition wires, a bad coil, a faulty ignition module, or even a bad injector(s). Even low fuel pressure can cause this type of issue. Also, a leaking fuel pressure regulator can make the vehicle hard to start and run rough.

I'd have to assume with it running so bad that the check engine light is on. I would recommend getting it scanned first and see what codes are stored and go from there. That would at least tell you what cylinders have the problem and you can then pinpoint your diagnosis on the correct area.
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robert1292
Posts: 5
Joined: Sun Jan 06, 2013 12:17 pm

Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by robert1292 » Mon Jan 07, 2013 5:24 pm

hello thank you, I did a scan and came up with some codes the mass airflow sensor and more evap codes too what should I fix?

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ProTech
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Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by ProTech » Mon Jan 07, 2013 7:53 pm

You might want to try replacing the Mass Airflow Sensor and see if that helps, which it could very well solve all your problems. As for the EVAP problems, I can't really help you without knowing the exact codes that were set.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

robert1292
Posts: 5
Joined: Sun Jan 06, 2013 12:17 pm

Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by robert1292 » Mon Jan 07, 2013 11:28 pm

ok thanks I have one more question I have cooant leaking out my tailpipe what could be the issue?? I don't have any codes comming up for head gasket or anything??

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ProTech
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Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by ProTech » Tue Jan 08, 2013 10:18 am

Oh boy, well now you have some real problems. I wouldn't waste any money trying to fix other issues, unless you plan on keeping the vehicle for a while and the rest of it is in good shape. With coolant coming out of the tailpipe, that means that coolant is getting in the cylinders. Usually this is the result of a blown head gasket, which will NOT set any codes.

If the van has a lot of miles, you might want to consider putting a used or new engine in it. A lot of times, if you replace the head gaskets on an older engine that is worn out or has not been maintained well, you'll just end up blowing the bottom end out of it.

I'd definitely stop right now and evaluate the situation, and whether it's worth putting thousands of dollars into or not.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

robert1292
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Joined: Sun Jan 06, 2013 12:17 pm

Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by robert1292 » Tue Jan 08, 2013 6:04 pm

it has 196000 km on it it has stopped right now because i put a stop leak in it and i plan on replacing the head gasket the upper and lower

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ProTech
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Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by ProTech » Tue Jan 08, 2013 7:02 pm

That is a horrible idea to try and take apart and fix an engine with 196,000 miles on it! You will definitely end up needing a new engine shortly after your repairs are done. Trust me, I've seen this many times over the years.

Why not take the money you were going to spend on parts and put that towards a good used engine? You can find quality used engines with a lot less miles for $800-$1000 at most reputable junk yards all over the country.

The 'stop-leak' you added will only cause further trouble and has now contaminated the entire cooling system and probably started to clog other cooling ports in the heads and block. You're really going about this the wrong way....just get a new engine, problem solved!
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

robert1292
Posts: 5
Joined: Sun Jan 06, 2013 12:17 pm

Re: 2001 Montana 3.4 hard to start and runs rough

Unread post by robert1292 » Tue Jan 08, 2013 8:01 pm

i don't have the money to pay for someone to install a whole new engine and a new engine

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