[Methos65]

Hello.
I have a 2004 ZX3 2.0L with about 80,000 miles and am having some engine performance issues. I’ll do my best to describe the symptoms. There are two basic issues and I’m not sure they are related as the second one did not occur today at all.

First Issue: For a while now, I’ve noticed that when driving, the car seems to “buck or jump” a little especially when I leave off the gas or even when I maintain it at a certain speed. I even notice a loss of power (briefly) when driving at speed. I’ve also noticed (by looking at the tachometer) that when coming to a stop, I usually shift to neutral and leave off the gas. The tachometer drops to 1k rpm and slowly moves down to about 600 rpm where it normally sits. As it moves down, the needle jumps a bit up and down.

Second Issue: Whether idling or driving at speed, the engine seems to “stutter” a bit and loses speed and power. It’s most noticeable when idling. The normal range is about 600 rpm for idle. I’m estimating that because the tachometer needle rests just under the second of two hash marks between 0 rpm and 1000 rpm. With the car in neutral and my foot on the brake, the engine stutters, the tach drops to the second has mark as if it’s going to stall, and then recovers back to normal. As I mentioned, I’ll notice this too when driving regardless of the gear or speed.

I’ve read many of the posts here and suspect several things may be contributing. Some of those are the EGR valve, spark plugs/wires, coil pack, fuel filter, vacuum leak, etc. I have not tried anything yet as I wanted to get some opinions first.

Thanks for reading and sorry for being long-winded!!

 

[oshoguno]

It could be anything. Sounds like you need to do a complete tune up first. Plugs, wires, fuel filter, PCV, air filter. If you still have the problems check the rear vacuum line to your intake manifold (engine cold so you don't burn yourself on something) to see if it is cracked or collapsing. These are all considered "consumable items" and would need to be done anyway so to properly troubleshoot your engine they need to be done first. A focus should idle at 800 RPM so if you normally idle and stumble at 600 I would address this problem first (PCV and vacuum line). Let us know how you make out.

 

[benkap]

It could be anything. Sounds like you need to do a complete tune up first. Plugs, wires, fuel filter, PCV, air filter. If you still have the problems check the rear vacuum line to your intake manifold (engine cold so you don't burn yourself on something) to see if it is cracked or collapsing. These are all considered "consumable items" and would need to be done anyway so to properly troubleshoot your engine they need to be done first. A focus should idle at 800 RPM so if you normally idle and stumble at 600 I would address this problem first (PCV and vacuum line). Let us know how you make out.

This. Make sure the basic maintenance is up to date and then it makes trouble shooting much easier.

 

[Methos65]

Will do. Thanks for the input.

 

[Methos65]

Funny....today, I had no issues whatsoever. Car ran like a champ. Cooler temps is about the only difference. I plan to do the tune-up items anyway though.