Hesitation when giving it too much gas.

[bluechro]

My MX-3 seems to be having some weird problems lately.. Whenever I'm driving the car and it's revving anywhere under 2500rpm, if I apply slightly too much pressure to the gas pedal, the engine just doesn't want to go. It makes a sputtering noise, and actually starts to slow down, as if it's not producing any power at all. I had spark plugs and spark wires replaced by a mechanic who knows his stuff a couple months ago, so I doubt that this is the issue. Has anybody had a similar experience, or anything to suggest at all? I'd really love to get it back running at it's prime.

EDIT: It's a '96 4cyl.

[Ryan]

I have a similar problem. Not really a problem, but....

I think its just a bad tune. My intake meter is wrong resulting un a rich mixture, and my plug wires are ooold... It used to be waaay worse before I remember to plug my VC breather TPS back in (don't ask)

[Inodoro Pereyra]

There are 2 things that come to mind, that could cause such problem. One is cheap, the other one is...not.
Try replacing the PCV valve. Sometimes, when it gets stuck, it causes power loss. That's the cheap fix.
If that doesn't work, get rid of the catalytic converter. Sometimes when the car has a lot of miles, they get clogged, and the back pressure in the exhaust literally kills the engine. Of course, depending on your local laws, if the cat is the problem you may have to get a new one. That is the "not".
Good luck.

[umcamara]

His car is a '96 and OBD-II. There's a warm-up cat, as well as a main cat. The warm-up cat should not be removed since it has an O2 sensor directly upstream and downstream, and a catalyst inefficiency code will be thrown. The warm-up cat also apparently has the proper curvature for reducing the exhaust diameter from the manifold to the piping.

I have the same issue. I've got a P0170 engine code, meaning fuel trim malfunction. The engine is running too rich, and the ECU has reached the maximum leaning correction that it can provide. I've checked for vacuum leaks and run diagnostics on many different parts to no avail. I believe I've probably got a leaking fuel injector or a fubarred fuel pressure regulator. May be some things to check.

On a side note. Whenever I wash my engine bay, the water pools in the indentation in the valve cover. It then slowly slips past the spark plug wire rubber seals and into the spark plug wells. Pools of water then build up in each well and the spark gets directly shorted to the block. This causes the engine to misfire terribly, and do what you're describing. I remedy this by pulling each plug wire and blowing the water out with compressed air. Runs fine afterwards.

Just some things to check.

[Redline322]

It sounds like it could be either a timing issue or it's possible there could be a crack in your intake tube and when you give it too much gas, the engine moves, expanding the crack.

[bluechro]

And now I remember why I love this community so much You guys are amazing.

I've recently replaced spark plugs and wires, so I don't think that's the issue. I'll try the timing and the PCV valve, see if that does anything. I haven't washed the engine bay in recent memory, so I don't believe the water would be an issue, but I'll take a look. Is it worth bringing it to a mechanic and seeing what they come up with? I don't mind doing it myself if it means replacing a couple parts, but I really don't have the time to fiddle with dozens of things until I find the issue.

[Inodoro Pereyra]

Well, as far as I'm concerned, I'd never even think about taking my car to a mechanic.
But of course, that's gonna be your decision, but if you can find your way around the engine, I'd recommend you do it yourself, at least until you exhaust your options.

[SuperK]

can't you take it to a auto parts store and ask them to check the codes? It's OBDII, right, and they have code checking service provided for free, right?

Sounds like it could be an oxygen sensor or air filter... You never said you replaced those recently.