Hello!
Recently I have been running into engine troubles. I have a 2000 limited 4WD with an auto trans and the 3.4L V6.
The other day when I was trying to leave work, my engine began running a bit rough. I made it to the intersection across from my work and I stopped at the light facing uphill, maybe a 10-15% incline if that. When I stopped, my idle began dipping down and struggling to get back up. It would go from like 600 ish down to like 100-200 and kinda of go up and down in that range. As soon as the light turned green, I gave it some gas and it stalled. I panicked a bit, so I hit the brakes, turned the key off and restarted it. I managed to just barely get up and around to head down the hill to my work turn - the car was running very rough and had barely any power. As I was heading up the drive to my work, the engine stalled again. I tried restarting but had no power to go up the hill (just a slight incline again). Luckily some of the guys from my work noticed and towed me into our lot. In the lot, I parked in a spot and just let my car idle. It sounded somewhat like drag cars with modified cams - kind of like these
YouTube . For a second I was like that's kinda fun but also realized I have a major problem. I figured the problem was probably something to do with fuel - and the fact that I was missing my second 02 sensor - the one right between the cat and the muffler. So I went to advance auto and got some BG44k and an 02 sensor. I put in the BG and the engine almost instantly started running better. A bit of running on the road I noticed there was a smell similar to old boats or dirt bikes - but the engine was running better. I then put in my 02 sensor and figured problem solved for now.
That was a couple weeks ago. However, I recently did some offroading with a buddy and had pretty much the same problem. After going through a puddle (not the first - we had splashed through like 5-6 others before and had no problem), I turned to head uphill and got the same loping and lack of power. Enough that once again, my engine stalled. I restarted it and this time it started running normally - a bit rough still - but enough that we were able to get off the trail. I noticed on flat ground and downhill it seems relatively fine. It is only uphill that the power really starts dogging, and it gets the sort of missfire - loping issue. I put more fuel cleaner in, and that helped once again but I am just worried this is going to come bite me again and I will get stranded somewhere or worse.
A couple things to note-
No CEL or codes either time
I did do some readings the first time it was running rough - noticed it was getting random misfires - but didnt trigger CEL
Newish plugs and wires (new enough they shouldn't need to be replaced yet.)
Applying throttle while engine was loping/missfiring didn't seem to have much effect. Only increased average rpm of maybe 100.
All maintenance is relatively up to date - oil change, battery, fuel filter, timing belt/pump, plugs, wires, etc all within 1-2 years
I believe it is running slightly rich - occasionally it is smellable
Seems to have lower power while driving until it reaches about 3000 rpm, with a noticeable increase in power - almost like turbo lag
I have not done anything like ISR or Deckplate mod - but I do have a lift with 33's
I am going to start with pulling plugs and wires and just seeing how they look. If anyone has had a similar problem or has any advice I would appreciate your comments - I consider myself mechanically handy but I do not have much experience with complex engine issues.