My max has recently had a new injector put in, plus new plugs and a tank of premium plus ACDelco fuel system cleaner for cleaning the injectors just today.

It runs very well, but not as well as it did when I got it. It stumbles a bit when I really stab the gas, esp. at idle. It'll shake, stutter for as second, and then rev. It also shakes a bit and has an occasional *plap* from the exhaust at idle. I'm trying to think of why it would do this. For the most part its a good runner and driver.

The plugs are new today. The wires were replaced at christmas wth NGKs. The cap/rotor were done while after I bought the car (cheap NAPA echelins) The injectors are all good. Why is it still running a bit oddly? I'm trying to thnk of why it would...

I remember when I put the cap and rotor on, it ran kinda crappily for a minute and then ran really well. I'm 90% sure I put the rotor on the same way the old one was...I'm assuming the car would run really really badly if it was on backwards? Right? Maybe my napa cap and rotor are crappy? They look fine underneath. Any other ideas on my rev stumble and slight idle strangeness? The way it ran for that short bit after I got the cap and rotor on is making me think now :\

 

How do you reset the ECU/computer? Pulling the battery for a while?

 

Any ideas?

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Possibility of another injector being bad. Also, double check the gap on the spark plugs. Maybe a bad coil pack.

I have a lot experience with Napa stuff... A LOT OF IT. And they really don't go out that often... surprisingly. But they still don't last as long as other manufacturers. And defects have been known to show up.

There's a possiblity of the ECU still having a code, but I don't think the chances are great on that. If the batter was disconnected while the injector was being changed, that was time enough to clear it.

 

possible another injector.
or more likely that ine injector is working great and the others can't keep up

 

The garage checked all of my other injectors and told me they were great, so I've pretty much ruled that out.

When I checked the cap and rotor last, there was some white stuff on the metal bits of the cap, and the rotor, but not much...maybe thats an issue? The parts were new, but the parts and hte boxes they came from looked like they'd been sitting damn near forever in the dumpy little Napa we have here. I can get a Bosch cap and rotor for cheapo...I might just replace anyway.

 

Would the coil cause this issue? I wouldn't think so, but who knows...

It seems like the more I'm driving it now, the better its getting...hopefully the injector cleaner is doing its work.

 

Hi,

another you should check on your engine, is see if the o2 sensor been replaced, if it the original then there possible your problem could be there,

 

Actually, the car's o2 was replaced just before I bought it, and I have hte receipt to show it. The car failed emissions and then had the sensor put on.

 

I'm going to get a Bosch cap and rotor and see how that does it. Probably won't solve it, but eh.

After thinking about it for a while, the car did run really poorly after the new cap and rotor went on, and when it smoothed out, it still didn't run as good as a car would after its ancient ancient ancient Hitachi stuff was pulled off.


My FSM says that if the engine is stalling when you step on the gas momentarily, the first step is to pull off hte AAC valve harness and see if the engine speed drops. I was going to, but it'll have to wait as I can't reach the thing with the intake in place :| But my car only stumbles a bit...doesn't stall.