Sputtering and Misfire issues in Drive and Reverse

[Smokin3161]

Hi, I recently did a tune up on my 98 Malibu LS... For the first few days it was fine and ran amazing. Recently when I'm idling at a light or in reverse under 10mph it sputters or maybe misfires.

I have checked to make sure everything is seated fine, tight and in correct order. Its very annoying and never did this before. I'm used to driving foreign cars and new to American cars IE my first Chevy. Can someone please shed some light?

Also I put my hand over the tail pipe and noticed the exhaust wasn't flowing freely, but like I said this didn't happen until I did the Tune up.

[Smokin3161]

Does anyone have any answers? I figured coming here would help....

[RalphP]

Check all vacuum hoses. I've had to replace a few on my 2000.

Especially the one from the PCV valve, under the throttle cable bracket (where it connects to the upper intake) and back to the EGR valve.

RwP

[Smokin3161]

Originally Posted by RalphP

Check all vacuum hoses. I've had to replace a few on my 2000.

Especially the one from the PCV valve, under the throttle cable bracket (where it connects to the upper intake) and back to the EGR valve.

RwP

I checked all my vacuum lines that i was able to locate, all seemed intact and connected. Any other suggestions?

[RalphP]

Time to drag out the timing light and verify engine timing - you may have a jumped timing chain (not likely!)

Also, triple check ALL wiring. One suggesting is to take a dark night, start the car, and fog the plug wiring with a mist of water.

In my personal experience, #1 and #3 spark plug wires are right royal pains in that it's easy to feel like they're on, but they'll jump right off. I had #4 cylinder give me fits my first tune up until I finally got it seated properly.

Also, there's a chance a coil pack has failed or is failing. This would tell you (the misting with water) due to the corona and sparking you'd see.

It's also time to check the fuel line pressure with a fuel line pressure gauge (they're cheap at Harbor Freight, albeit not very accurate.)

RwP

[Smokin3161]

Originally Posted by RalphP

Time to drag out the timing light and verify engine timing - you may have a jumped timing chain (not likely!)

Also, triple check ALL wiring. One suggesting is to take a dark night, start the car, and fog the plug wiring with a mist of water.

In my personal experience, #1 and #3 spark plug wires are right royal pains in that it's easy to feel like they're on, but they'll jump right off. I had #4 cylinder give me fits my first tune up until I finally got it seated properly.

Also, there's a chance a coil pack has failed or is failing. This would tell you (the misting with water) due to the corona and sparking you'd see.

It's also time to check the fuel line pressure with a fuel line pressure gauge (they're cheap at Harbor Freight, albeit not very accurate.)

RwP

I will try these suggestions, I stopped to see my buddy today and he told me to check the gap on the plugs. I think they came pre gapped but Im going to pull them all and see.