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Discussion Starter #1
So, 4 months ago I decided to say "**** it! I'm going to explore the country and find a new place to call home!"

I got rid of all my stuff and jumped into my super reliable 1998 buick park avenue and hit the road working odd jobs for gas money.

a few weeks into it I had I had coolant loss.

No worries! I had a new plenum and gasket set it the trunk! When I was dismantling the car on a forest road I noticed that the plenum bolts were basically finger tight. "Aha!" I said! This is my issue!

So I just changed the plenum and gasket and called it good. Changed the spark plugs too. Front 3 because the back were hard.


Everything was great for another two months.

Driving from phoenix to vegas I got a misfire and the CEL cane on.


Hit an auto parts shop for a code scan.

Misfire cylinder 1
Egr valve

Googled it. Egr valve can cause misfire

Cleaned it.

Erased codes.

CEL again

Misfire cylinder 4

Ugh.

Swapped coil packs. Erased codes.

CEL again.

Random Misfire.

Google suggested intake manifold leak.

Did that.

I misread the torque as foot pounds I stead of inch pounds.

When I was tightening them, it didnt feel right, so I torqued them by hand to what I felt was tight.

I tossed out the torque wrench idea and wrist tightened the UIM

Nope. Still misfire.

Exhaust smells like gas.

Wasnt making money in vegas. Drive my ass back to Phoenix.

That morning I noticed I had a bad sparkplug wire on cyl 1

Drove to work to get money to bit new wires.

Started it up. Sluggish performance!

Changed wires. Seemed to help for a minute. It didnt.

Maybe bad cat from driving with a misfire a few hundred miles?

Popped out the upstream o2 sensor. Didn't seem to help.

Bought new plugs and replaced all 6 (the back 3 were way easier than I expected)

Replaced it.

Eventually started thinking I had cracked the plenum. Inspected and saw a little coolant leak in front. Saw it was slightly cracked by a bolt by the alternator



Bought a new plenum and a proper inch pound torque wrench anyway.

Did it right.

Still having issues

It seems like a vacuum leak.
Did a smoke test with my e cig blowing in the brake booster hose into the plenum with the throttle body sealed with plastic. It seemed very solid and I saw zero smoke.


Ive sprayed carb cleaner everywhere! Nothing changed.

I removed the throttle body today. Dirty as hell. Inspected the egr pipe. Its solid.

Replaced the throttle body and drove off. It was almost stalling. Idle was jumping up and down! Omfg!

Googled it.

Google said I might have fucked up the throttle position sensor by opening and closing it too fast.

Maybe the IAC?

So. I bought throttle body cleaner and .MAF sensor cleaner.

Opened the hood. Ahh. I had forgot to attach the vacuum hoses to the throttle body-

Removed the throttle body. Removes the MAF sensor with my new 15 dollar security torx bit set (****)
Soaked the throttle body. Scrubby scrub scrub with the tooth brush.

Installed it. Started it spray the throttle body cleaner at idle and while revving it.

Cleaned the MAF.

It feel like there is a improvement. But its still lugging on acceleration. But not as bad as before.

Drives fine on the freeway on flat ground. Sucks up long grades. I'm going 45 with my flashers on.

Im going to have my cat checked out at a shop tomorrow.

Im going to inspects the spark plugs again tomorrow.
Im not seeing coolant in oil or oil in coolant. Exhaust smells fine and isn't colored

Any ideas?

Can I remove the lower intake manifold to inspect without installing a new gasket?

Did I **** up the intake manifold by torquing it wrong?


Should I buy a used manifold from a used parts place and new gasket and redo the LIM?

Any suggestions would be super awesome!

And yes.my road trip vacation has been a whole lot of heck this last two weeks and I'm now in a city I like, an familiar with, and am looking for a real job instead of ra com day labor for gas money. Lol. Damn.
 

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There are way more experienced techs on this site than me, but I'll give you my thoughts.

Do you have the ability to verify vacuum? On Lesabres of the same era, there is a vacuum reservoir inside the passenger front fender. The vacuum also runs the air vent diverters in the cabin, and I've seen the hoses crack, break or come off entirely. On my 97, I had the vacuum hose slip off a check valve under a plastic cover on the firewall. I knew to look for it, as the airflow to the vents changes when you go up hills when the vacuum is not high enough (e.g. goes from front to feet or defrost going up a hill). I've seen that on several 3.8l Buicks and obviously loss of vacuum is a problem for these cars.

I don't think this is your issue all things considered, just something easy to eliminate.
 

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So, 4 months ago I decided to say "**** it! I'm going to explore the country and find a new place to call home!"

I got rid of all my stuff and jumped into my super reliable 1998 buick park avenue and hit the road working odd jobs for gas money.

a few weeks into it I had I had coolant loss.

No worries! I had a new plenum and gasket set it the trunk! When I was dismantling the car on a forest road I noticed that the plenum bolts were basically finger tight. "Aha!" I said! This is my issue!

So I just changed the plenum and gasket and called it good. Changed the spark plugs too. Front 3 because the back were hard.


Everything was great for another two months.

Driving from phoenix to vegas I got a misfire and the CEL cane on.


Hit an auto parts shop for a code scan.

Misfire cylinder 1
Egr valve

Googled it. Egr valve can cause misfire

Cleaned it.

Erased codes.

CEL again

Misfire cylinder 4

Ugh.

Swapped coil packs. Erased codes.

CEL again.

Random Misfire.

Google suggested intake manifold leak.

Did that.

I misread the torque as foot pounds I stead of inch pounds.

When I was tightening them, it didnt feel right, so I torqued them by hand to what I felt was tight.

I tossed out the torque wrench idea and wrist tightened the UIM

Nope. Still misfire.

Exhaust smells like gas.

Wasnt making money in vegas. Drive my ass back to Phoenix.

That morning I noticed I had a bad sparkplug wire on cyl 1

Drove to work to get money to bit new wires.

Started it up. Sluggish performance!

Changed wires. Seemed to help for a minute. It didnt.

Maybe bad cat from driving with a misfire a few hundred miles?

Popped out the upstream o2 sensor. Didn't seem to help.

Bought new plugs and replaced all 6 (the back 3 were way easier than I expected)

Replaced it.

Eventually started thinking I had cracked the plenum. Inspected and saw a little coolant leak in front. Saw it was slightly cracked by a bolt by the alternator



Bought a new plenum and a proper inch pound torque wrench anyway.

Did it right.

Still having issues

It seems like a vacuum leak.
Did a smoke test with my e cig blowing in the brake booster hose into the plenum with the throttle body sealed with plastic. It seemed very solid and I saw zero smoke.


Ive sprayed carb cleaner everywhere! Nothing changed.

I removed the throttle body today. Dirty as hell. Inspected the egr pipe. Its solid.

Replaced the throttle body and drove off. It was almost stalling. Idle was jumping up and down! Omfg!

Googled it.

Google said I might have fucked up the throttle position sensor by opening and closing it too fast.

Maybe the IAC?

So. I bought throttle body cleaner and .MAF sensor cleaner.

Opened the hood. Ahh. I had forgot to attach the vacuum hoses to the throttle body-

Removed the throttle body. Removes the MAF sensor with my new 15 dollar security torx bit set (****)
Soaked the throttle body. Scrubby scrub scrub with the tooth brush.

Installed it. Started it spray the throttle body cleaner at idle and while revving it.

Cleaned the MAF.

It feel like there is a improvement. But its still lugging on acceleration. But not as bad as before.

Drives fine on the freeway on flat ground. Sucks up long grades. I'm going 45 with my flashers on.

Im going to have my cat checked out at a shop tomorrow.

Im going to inspects the spark plugs again tomorrow.
Im not seeing coolant in oil or oil in coolant. Exhaust smells fine and isn't colored

Any ideas?

Can I remove the lower intake manifold to inspect without installing a new gasket?

Did I **** up the intake manifold by torquing it wrong?


Should I buy a used manifold from a used parts place and new gasket and redo the LIM?

Any suggestions would be super awesome!

And yes.my road trip vacation has been a whole lot of heck this last two weeks and I'm now in a city I like, an familiar with, and am looking for a real job instead of ra com day labor for gas money. Lol. Damn.
 

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I fixed a friend's Lesabre using the following link, which shows you how to narrow down misfire issues. Replacing the coil packs was a good idea, but her problem turned out to be the ignition control module. A cheap used one from a local yard fixed her misfire issues.

 

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Have you tested fuel pump delivery and pressure??? Look at some GM manuals for your model and then test your fuel delivery volumn (1 pint in 30 seconds) and correct pressure......you might be running TOO LEAN......... Jake
 

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Discussion Starter #6
I forgot about making this post.

So, funny story, it was a coil pack.

The coil pack failed in the time between diagnosing the spark plugs and wires failure and replacing the spark plugs and wires.

After driving from Phoenix to northern Idaho on 4 cylinders and I had a friend crank the engine while I popped the wires and sure enough, the damn coil pack was bad.


I replaced it and it's been working like a charm.

Lol.

$25 for the coil pack, $25 for the wires, instead I spent hundreds and hours of labor and hours of research :)
 

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Glad you found the problem. Normally when I see a problem like that one, checking wires, plugs,fuel delivery, ignition system are the first things I check before digging in too deep in the wrong direction. Generally with issues like you described usually turn out to be ignition problems or fuel delivery issues. Keep up the good work and share what you found with others. Thanks for your reply......Jake
 

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Discussion Starter #8
In hindsight, the funny part was the entire issue was the first things suggested.

But, on the bright side, I won't be having a LIM Gasket failure.

I bought and learned how to PROPERLY use a torque wrench as well as how to torque in sequence.

I also cleaned the Throttle idle valve, throttle body, replaced cracked vacuum hoses, learned how to do a smoke test with an electronic cigarette.

I did the entire UIM/LIM Gasket repair 2 times, and the UIM only gasket repair 2 other times, so I'm pretty much a pro at it now, so if I ever meet anyone with that issue, I can help them out :)

I even recently replaced a broken motor mount with hands off supervision from a friend.

I'm pretty emotionally bonded with the GM 3800 engine now.
 
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