When driving up hill check engine light turns on

MERCHQUEEN

MEMBER
2003 BUICK LESABRE
3.8L
6 CYL
2WD
AUTOMATIC
238,000 MILES

My car just started flashing the check engine soon light when I try getting up a hill. I level off and the light goes off. Runs not very well up hill either. My code reader, will not give me a code. Seems to be getting worse. Help!

Saturday, December 5th, 2020 AT 12:01 PM

11 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

You have a misfire when the light flashes.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

How old are the plugs and wires? They are very common reasons for the misfire.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

I would start with a set of spark plugs and see if the condition still exists.

https://www.2carpros.com/articles/how-to-change-spark-plugs

Roy

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Wednesday, December 9th, 2020 AT 3:55 PM

MERCHQUEEN

MEMBER
6 POSTS

3 plugs in today. 3 to go. 3 rear in. 3 front to go. The all day long ones job. I needed to drive it today, for 110 miles. Missed on several hills, but plugs are only half done. I will keep you posted. You are a saint and again, thank you so much for your help! You have been a bright spot in a not so bright year Expensive car repairs, I can't afford now, but I am still lucky and am an essential worker and need to work. Bless you. Thank you again.

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Wednesday, December 9th, 2020 AT 5:06 PM

MERCHQUEEN

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6 POSTS

Sunday new plugs/wires. It is still missing on 2 cylinders. Antifreeze on engine also. Help do I have a car yet or not? What else can it be? Intake manifold/gasket?

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Sunday, December 13th, 2020 AT 4:17 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Okay, yes, it could be a leaking intake manifold in to one of the runners.

I would pressure test the cooling system to be sure.

https://www.2carpros.com/articles/radiator-pressure-test

https://www.2carpros.com/articles/replace-intake-manifold-gasket

I attached the procedure below for you to view.

Roy

1. Remove the upper intake manifold.
2. Remove the thermostat housing.
3. Disconnect the electrical connector from the ECT.
4. Remove the drive belt tensioner.
5. Remove the EGR valve outlet pipe.
6. Remove the lower intake manifold bolts.
7. Remove the lower intake manifold.
8. Clean and inspect the lower intake manifold.

Installation Procedure

Important: In order to install the manifold, complete the following steps:
Clean the cylinder block, heads and the intake manifold sealing surface of all oil with a suitable solvent.
Apply a GM approved sealer to the ends of the intake manifold seals. Clean any adhesive compound from the intake manifold bolts and the bolt holes.
Apply thread locking compound GM P/N 12345739 (Canadian P/N 10953541) or equivalent to the intake manifold bolt threads before assembly.

imageOpen In New TabZoom/Print

1. Install the lower intake manifold gasket.
2. Install the lower intake manifold.
3. Apply Threadlocker 272 GM P/N 12345493 (Canadian P/N 10953488) to the bolt threads.

Notice: Refer to Fastener Notice in Service Precautions.

imageOpen In New TabZoom/Print

4. Install the lower intake manifold bolts.
Tighten the lower intake manifold bolts in sequence (1-12) to 15 Nm (11 ft. lbs.).
5. Install the EGR valve outlet pipe.
6. Install the drive belt tensioner.
7. Connect the electrical connector from the ECT.
8. Install the thermostat housing.
9. Install the upper intake manifold.

Images (Click to make bigger)