'01 Rodeo, surging weird on hard acceleration


jostby
03-03-2010, 04:38 PM
I recently had a head failure (3.2 V6). I replaced the head (had both of them rebuilt at that time). replaced timing belt, etc.
Now when you take off from a stop and romp on it, it used to be like a rocket. Now it takes off good but starts to kind of surge almost like you are letting off the throttle just a little and then flooring it again. It happens right when the power seems to come on good, like something is dialing the horsepower back a little, over and over again. Once it hits 3500rpm it's OK from there up.
Has anyone experienced this same problem? It doesn't surge at cruising speeds, only under hard acceleration.
It is also occasionally shifting odd and "clunking" when it shifts and has never done that before either. After reading through the FAQ pages I am going to load test my battery tonight and check the amperage and voltage output of my alternator as I read a bad battery can possibly cause this?
And some days it drives perfect with perfect power???
Laying in bed at night I can also visualize an injector going bad, fuel pump, or possibly the plugs but there have been no CEL's and no stored codes found by AutoZone
Thanks for any help.
Jeff.
2001 Rodeo
3.2
105,000 miles

jostby
03-03-2010, 08:48 PM
OK, battery load tests just OK, drops to 10V with 320amps after 15 seconds (640A battery). But charging is at 13.8V constant. Everything I have read says these things need 14.4V?
Alternator is putting out 75A max.

Any input?

Thanks,
Jeff.

jostby
03-07-2010, 01:10 PM
Anyone??

amigo-2k
03-07-2010, 09:55 PM
My guess is the timing is off. Read up in the FAQ's to see if you are a few teeth off.

jostby
03-08-2010, 07:53 PM
Thanks for replying but you missed the part where I said that "And some days it drives perfect with perfect power"
But at this point the issue is getting worse. Those "some days" aren't happening much.
My wife has gotten the "blinking" CEL (never a steady CEL) but it hasn't ever happened for me. Until yesterday.
Test driving (again), it started popping like misfiring real bad when trying to accelerate after turning onto the highway and heading uphill. Was really running like a dog and I was getting :banghead: . I held my foot on the throttle and it popped and bucked (intake backfiring) and that set set the light off. Pulled over and checked it, P1311 (ion sensing module) and P0101 (MAF sensor). I think the MAF sensor was set off because of the backfiring. The Ion sensing was something I think will tie in to the way it feels like the timing is being advanced and retarded (see my 1st post how the power seems to surge).
I cleared the codes and limped it home (still running like sh**)
Today the wife takes it to work and again gets the flashing CEL, then it turns solid but still flashes over 1600rpm. I talked her through checking it with the code reader. This time it's the code for multiple misfire (can't remember it at the moment), plus the MAF code again, which I suspect keeps getting set off by the backfiring.
SO, yesterday I ordered plugs from sparkplugs.com (2-day delivery) even though my last set of Denso's are only about 30,000 old. Keep in mind none of this was happening before this engine took a dump. AND, like I said before, sometimes it will start and run perfect the whole time (a 20 mile trip).
I have also tried Lucas injector cleaner with Premium gas thinking maybe something went foul the 2 months this car was down.

I still look forward to hearing any suggestions but will also update when I find the cure. At this point I am waiting for the plugs. If I still have issues I will replace the Ion Sensing Module (only because the local wrecking yard has one though). If that isn't it it's possible there is a wiring issue but since I did all of the work I know that I was very careful with the haness and plugs.

Thanks,
Jeff.
2001 Rodeo 3.2
105,000 miles

amigo-2k
03-08-2010, 08:05 PM
The last time I had a misfire was due to loose plugs.

jostby
03-13-2010, 11:10 PM
Loose plugs. :eek7: Yeah. :eek7: 27yr (47yr old) journeyman diesel mechanic here. I was actually looking for some feedback that might actually be past the "just-out-of-high-school-flipping-burgers" type of reply.:screwy:
I finally had it towed to a shop because it has kept running worse and worse. First actual repair that I will have ever paid anyone to do in my life (other than a/c just because the equipment is cost-prohibitive). Trusted friend owns the shop, says 1 or both CAT's are plugged. If that doesn't turn out to be the problem I will continue to post just in case someone else actually ends up having the same issues as I have and ends up searching this forum for clues. I'm still unsure (skeptical) what may have caused the failure so sudden.

Thanks anyhow.

Jeff.

anthonyn
03-14-2010, 02:36 PM
Check the O2 sensor(s) also. When mine started to go, the car just started running worse and worse as time went on. I also envisioned bad fuel pump, plugged cat, leaky injectors etc. I replaced the O2 sensor, spark plugs and cleaned the EGR valve and now the vehicle runs like new again.

jostby
03-14-2010, 05:21 PM
Check the O2 sensor(s) also. When mine started to go, the car just started running worse and worse as time went on. I also envisioned bad fuel pump, plugged cat, leaky injectors etc. I replaced the O2 sensor, spark plugs and cleaned the EGR valve and now the vehicle runs like new again.

Did you get any CEL or fault code to indicate the sensors weren't working properly? And did you end up with plugged CAT's?

I'm not sure how close your 95 would compare with the difference in electronic controls used on my '01.
I almost have to assume that something related to me pulling the engine caused this failure. One thing I did was reuse the exhaust seals/rings between the manifolds and pipes because the ones from NAPA and Schucks/Krager or whatever they are called in your area didn't fit (and they couldn't match one either) and the dealer wanted $25 each (x2) plus freight. Didn't sound like I had an exhaust leak but I guess if I did it may have contributed to overfueling and the converter issue.
Jeff.

anthonyn
03-14-2010, 06:31 PM
No CEL. Mine is OBDI so CEL rarely comes on for anything.

When O2 goes bad it changes the fuel mixture, and that can affect shift points. So tranny feels weird. One mechanic said I had a dying tranny. Not True! At the beginning, when I accelerate, like driving 50mph, then accelerate to pass someone, there would be a moment's hesitation before the power kicked in. As the days went by, the car just ran worse and worse all the time- sluggish, lack of power, hesitation at all speeds.

There are some similarities with your symptoms and what I experienced I think. I don't think an exhaust leak so small that you didn't notice it would lead to a plugged CAT so quickly.

Just wanted to add, O2's don't kick in till the car warms up. After the O2 replacement car is running great - no plugged CAT. Plugged CAT is obviously a symptom of something else, so you still have to track down the root cause. Good luck.

jostby
03-15-2010, 04:28 PM
The wife had been out of town until last night. When she asked what could have cause the CAT failures I told her possibly failed O2 and running rich. She say's "Don't you remember I told you I could smell gas every now and then". Hmm, uh, yes I guess you did. One of those "but it never happens when I drive it" things.
Dang this is going to be expensive by the time it's all done. On the plus side we have never had to put any money into this car other than routine maintenance so I guess it evens out over the long run. Still hurts though.

Jeff.

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