Quad 4 problems

Quad 4 problems are very common and will be discussed here but first some background and history of this general motors engine.

This engine is a high rpm dual overhead cam 2.3-liter inline 4 cylinder. The motor was first introduced in 1988 in Olds and Pontiacs and then made its way to the Buick line in 1990. This engine was later punched out to a 2.4 liter version.

The first thing most people wonder when they see a Quad4 for the first time is, where are the spark plugs and wires located. The ignition is a Distributor less Ignition System (DIS).

There are no plug wires like you may be used to. There is a cover on the engine that says Quad4 on it; this cover is removed to access the plugs.

Quad 4 engine miss

Here is an e-mail I fielded about a quad 4-engine misfire coupled with a check engine light. You can read through this and look for a link at the bottom for a PDF you can save to your hard drive about other quad 4 problems that are common

Question or Comment: I have a 2001 Pontiac Grand Am with a 2.4L and Auto Trans, 74000 miles. Last week it started running very rough. Also the service engine light came on. I recently purchased an auto scan tool.

At first there were (2) codes for the same thing. P0303 CYLINDER #3 MISFIRE DETECTED. I pulled the spark plugs and they all were severely worn, so I replaced all (4) plugs gapping them to the recommended spec.

Upon re-starting the car, it ran great for a short time before the check engine light came back on. The engine also started running rough again. I plugged in my scan tool; this time the code was P0300 RANDOM/MULTIPLE CYLINDER MISFIRE DRTECTED. I tried doing some research, all I could think of trying was to replace the coil packs, which I did; however, it didn't make any difference at all.

Any help you can provide me with concerning this matter will be HUGELY APPRECIATED. THANK YOU FOR YOUR TIME & KEEP UP THE AWESOME WORK THAT YOU DO. YOUR CAR QUESTIONS WEBSITE IS AWESOME!

Answer to this quad 4 problem

Hello Scott: I have been down this road with a grand am (quad4) myself. The problem is the quad 4 I worked on was a 99 so things might be a bit different on your model!

I had the same codes (I replaced the plugs & the coils Also). To make a long story short the engine misfire was caused by what a quad 4 uses to replace the plug wires. The plastic housing that holds the coil packs and fits down over the spark plugs.

On the bottom of the housing is little boots that connect to the plugs. The coil housing itself contains copper (thin) runners to carry the high voltage spark from the coils to the plugs. My housing was bad (copper strips had hairline cracks) and acted like bad plug wires would (miss hot or under load).

When I went to the Pontiac dealer parts department they new all about it! They called this part a battle ship because the gray plastic housing held upside down looks like a battle ship. It sounds to me you are having the same problem causing your grand am to run ruff.

When I replaced my coil housing I also replaced my boots (the dealer called it a boot kit) Sorry I don't remember prices because this all happened 3 years ago. But I will never forget the battle ship!

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Note: Your newer quad 4 2.4L may have a slightly different set up? You may want to take a look at all-data for TSB's and diagnostic steps for other Quad 4 problems.

All-Data is offering a Free Demo through my link. The Demo AllDatadiy link is just under the testimonials link in the upper left hand corner of the white page area.

Hint: Once you find the Demo all-data has a search button on the bottom of each page to quickly find what you are looking for. Here is a link to The All-Data Website.

Quad 4 problems

Quad 4 engine miss

Answer to this quad 4 problem

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