I have a 2003 Montero Sport, 3.5L. I bought it in April. Plugs and wires were changed 20K Miles ago and I just did a timing belt. It has about 162K Miles on 'er now.

Recently a Service Engine Soon (SES) light came on. I got the code read and it was EGR related. It went off and I thought it was bad gas and I drove on (this was in late October). Then it got worse; the light stayed on longer and soon the idle was rough and low. I also got a DTC for a misfire in Cyl2. Here is what I've done so far:

1. Changed EGR Valve.
2. Changed ignition coil for Cyl 2.
3. Changed psx side exhaust mani (there was a crack)
4. Changed EGR Solenoid (primary).

At this point, I think the EGR system is okay, as I don't get that DTC anymore; however, now I get a "random misfire detected" DTC instead of one specific to Cyl 2 (although the codes were read with different readers and it's possible that the current reader is less capable than the one that initially read "cyl2.")

As for physical symptoms: the idle is still low/rough. I disconnected the IAC valve and that helps. It's really under-powered going up hills. It seems to hunt for gears. It smells "rich" still, from what my nose can tell.

Any ideas? I appreciate any help this forum can provide.

Thanks,
Erek

 

Start by checking the ignition wires to make sure they are seated all the way in the spark plug wells. If the wire is not all the way down, it may cause intermittent misfire.
Second - check (and re-check again) your timing. It is possible to have the timing belt off by one tooth and get a misfire/rich mix from that.

 

Thanks...both those suggestions make sense. Unfortunately neither is easy. The intake plenum blocks access to the spark plugs, and of course getting to the timing belt is a chore.

...wait. Can I check the timing without getting to the belt? Long ago I remember my Dad doing timing with a weird looking strobelight-gun thing. Is that still the way to do it?

 

Unfortunately, to check the timing belt you have to pull the covers off and do it on the engine while it's not running. What your dad was doing with the strobe light is checking spark timing advance. It's different from the timing belt.
These engines are compact and can be difficult to work on (i.e. taking the intake plenum to check spark plugs, etc.). I'd suggest you try to find couple of hours when you will not be distracted, get a beer and calmly check things out. Good luck

 

Have you replaced the fuel cap? If you haven't...its probably a good to replace it anyways. Also a bad seal on a old fuel cap could cause EGR codes.

 

...thanks all for the feedback.

I gave up and took it to a very reasonable indy mechanic I've worked with before. He just called. It was the Ignition Spark Module. He says it runs perfect now.

I suppose the EGR thing was real and I'm glad I R&R'd the valve and solenoid. The crack in the exhaust mani was real, so that's not a waste of $. I learned some stuff about this engine so that's not all bad.

....and the mechanic only charged me $280 (parts, labor, tax, everything) so all in all, that's not bad!