Solved Miss at acceleration with no codes.

[Ernie2]

2008 Merc Mariner 3.0 L 2 WD - I'm experiencing a bad miss when i accelerate from any cruising speed. The slightest additional pedal will cause missing and studdering until I let off the gas a little. I'm not getting any codes or check engine light. Thinking this may be an injector problem as I have no codes indicating a missfire or any other problem. Thought about a coil breakdown but assume this would throw a CEL.

Would appreciate any ideas or assistance. Need some direction before I tear into it. I have a code reader that will monitor PIDs but not sure exactly what look for..

Thanks in advance, Ernie

 

[BrooklynBay]

Check the gap of each spark plug.

 

[Ernie2]

Thanks for the quick response, BB. I can certainly do that. Also I didn't mention above but the car runs great when first driven but develops the miss once it is fully warmed up. Hope this additional info will be another clue to the problem. Thanks again.

 

[BrooklynBay]

Check the intake manifold seals for leaks.

 

[shucker1]

How many miles on it?

My 98 did that one time and it turned out to be bad spark plug wires with 70,000 miles on them.

 

[shucker1]

Welcome to the forum!

 

[Ernie2]

Thanks for the welcome and thanks to BB &S1 for their input. Guess I'll be pulling the intake. Still don't understand why it's not throwing a code.

 

[BrooklynBay]

Spray intake cleaner on the outside of the seals while the engine is idling to see if the idle changes.

 

[Ernie2]

Just want to close this out. I finally got a CEL for a misfire on #4. I swapped the coils from #4 & 5, reset the CEL and drove until I got another CEL. This time a misfire on #5. Aha! Since the problem followed the coil, I replaced the the coil I moved to # 5 and whala, problem solved. Bad coil. Thanks for everyone's input.

 

[shucker1]

Not so fast brother.

You gotta hang around and help other folks out.

It's the unwritten rule.

 

[BrooklynBay]

Thanks for the update. Your thread is now marked as solved.

 

[Ernie2]

Actually I was around a lot when I had my 96 X. Put over 300k on it before she gave up the ghost. This place was always very helpful. Now dealing with my 08 Mariner. I'll be around and always ready and willing to help when I can.