1998 2nd Gen Escudo/GV H25 V6 - random idle stutter/jolt

Chances are your one might not be obd2, we didn't get obd2 until 2006. Some vehicles had it from about 2000 on.

Max will no doubt stumble on this post and give you some pointers on the diagnostic plug.

You're looking at the wrong "plug" - the one you want is on the driver's side inner fender, it's usually attached to a bracket alongside the strut mount and may have a rubber cap over it.

I'm not certain what you mean by "scavenging", but my bet is the EGR valve is not closing properly - the reason you can't reproduce it in the driveway is the EGR won't open if the vehicle is not moving, it will open under cruise conditions, and if you lift off the throttle so that the vehicle is rolling because of it's momentum, it will be open & close just as the engine reaches idle speed, if takes to long or doesn't close properly, the engine stumbles & may stall as the vehicle comes to a stop.

fordem said:

Check Engine Light

You're looking at the wrong "plug" - the one you want is on the driver's side inner fender, it's usually attached to a bracket alongside the strut mount and may have a rubber cap over it.

I'm not certain what you mean by "scavenging", but my bet is the EGR valve is not closing properly - the reason you can't reproduce it in the driveway is the EGR won't open if the vehicle is not moving, it will open under cruise conditions, and if you lift off the throttle so that the vehicle is rolling because of it's momentum, it will be open & close just as the engine reaches idle speed, if takes to long or doesn't close properly, the engine stumbles & may stall as the vehicle comes to a stop.

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i was going to post something about this issue Gatman was having; because I have had the same thing happen to me yesterday for the first time. I've got a 2004 Vitara 4x4 5speed with the H25 V6 motor. Currently 214k miles on the vehicle.
Mine was Exactly as described; never had it happen before. With mine the idle dropped at a stoplight down to maybe 400rpm,stayed there, then came back up to regular idle as I applied gas to move away from the light. It happened just that one time and nothing else since.

What would be the best course of action to clear up this problem? A OBD2 scan shows no codes. I've had an old GM product ('85 chevy S-10 blazer with the infamous 2.8 litre V6) and they had issues with the egr valve clogging up to the point they were completely sealed off. is this a clean the EGR valve repair, or replace the EGR valve situation?

Many thanks in advance for your advice !

Honestly, given where the EGR is on the V6, I'd ignore it until/unless it starts doing it more often.

The EGR on these vehicles is a stepper motor design, the problem is most likely carbon build up between the valve and the seat preventing it from sealing properly - you might have had a one time occurrence with a spec of carbon that got displaced and blown out the next time the valve opened.

If it's not stumbling you'll never know if you've found & fixed the problem, so just leave it

fordem said:

Honestly, given where the EGR is on the V6, I'd ignore it until/unless it starts doing it more often.

The EGR on these vehicles is a stepper motor design, the problem is most likely carbon build up between the valve and the seat preventing it from sealing properly - you might have had a one time occurrence with a spec of carbon that got displaced and blown out the next time the valve opened.

If it's not stumbling you'll never know if you've found & fixed the problem, so just leave it

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Thank you! for your reply. And i am glad it's most likely not a situation where the EGR completely blocks off due to carbon buildup. My vitara is driven regularly and a lot of all kinds of driving, so the speck of carbon causing a 'hiccup" is entirely plausible.

I'll keep an eye on it but thanks again for the info.