Highway surging is now sputtering and low speed stalling
Posted: Sat Nov 26, 2011 2:31 am
I have read of the other problems out there, but not something with the surging turning into sputtering and then stalling like this.
Like many others on the forum here, I've had the surging problem on the highway. I've had this for maybe 6 to 8 months now. It hasn't been too severe. Typically it would show itself when
Today I was returning from the parts store (playing good Samaritan helping fix a water pump on a friends Olds), I was climbing a grade, 2000 RPM's, boost at 0, speed about 40, and the car did much more than the surging. This time it had more of a major miss, the RPM's went real low like about 1000, and the car slowed really fast. This was more of a sputtering like it was being starved for gas. I got off the throttle and back on it and it sputtered again. Speed was now down to about 25 MPH and the car was sputtering up the hill about 25% of the time. As the car got to the top of the hill, the sputtering stopped and all seemed fine again. About 1 mile down the road, I slowed to turn off a side street and the car stalled.
At this point, I parked it as I tried to fix the Olds (this didn't go well either), so it had time to completely cool off. It now was night and dark, so headlights are needed.
When I went to leave and go home, I started the car and saw headlights dim a tiny bit then return to normal brightness. At the time, I didn't think much of it. I began driving and the first stop was from about 15 MPH, no issue. I made the turn, got up to 35 MPH and at the next stop, the headlights dimmed and the car stalled. After seeing the dimming and stall, I decided I needed to observe the battery voltage on the DIC and RPM's on the tach. I noticed a pattern forming.
Am I taking the right steps in the right order? Input from the collective experience of the board is appreciated.
Thanks
Like many others on the forum here, I've had the surging problem on the highway. I've had this for maybe 6 to 8 months now. It hasn't been too severe. Typically it would show itself when
- at a speed between 35 and 65
- RPM's around 2000, but sometimes as high as 2500
- RPM's will go up and down by about 150 or so when surging begins
- boost at 0 to 5 PSI
- climbing a grade
Today I was returning from the parts store (playing good Samaritan helping fix a water pump on a friends Olds), I was climbing a grade, 2000 RPM's, boost at 0, speed about 40, and the car did much more than the surging. This time it had more of a major miss, the RPM's went real low like about 1000, and the car slowed really fast. This was more of a sputtering like it was being starved for gas. I got off the throttle and back on it and it sputtered again. Speed was now down to about 25 MPH and the car was sputtering up the hill about 25% of the time. As the car got to the top of the hill, the sputtering stopped and all seemed fine again. About 1 mile down the road, I slowed to turn off a side street and the car stalled.
At this point, I parked it as I tried to fix the Olds (this didn't go well either), so it had time to completely cool off. It now was night and dark, so headlights are needed.
When I went to leave and go home, I started the car and saw headlights dim a tiny bit then return to normal brightness. At the time, I didn't think much of it. I began driving and the first stop was from about 15 MPH, no issue. I made the turn, got up to 35 MPH and at the next stop, the headlights dimmed and the car stalled. After seeing the dimming and stall, I decided I needed to observe the battery voltage on the DIC and RPM's on the tach. I noticed a pattern forming.
- speed over 30 and slow to a stop
- lights will dim and voltage on DIC shows dropping to battery voltage only, voltage is usually 14.6 - 14.9, it drops to 13.x, then down to 12.x as if the alternator has failed
- if I give it some gas it may recover from this low voltage condition and return to 14V solid as if there is no problem with the alternator
- if the car is slower than 20, it usually doesn't recover and stalls
- I've tried to put it in neutral, give it gas to keep running and brake with the other foot, this kinda works, but I don't brake well with the left foot
- only sputtered once on the way home, giving more gas did not drive through the sputtering like would happen with the previous surging issue
- car has 141K miles on it
- car did kick out the MAF code P0102, reset code, didn't come back with 6 stalls, but did come back after 7th stall
- car has had an EGR code off and on. Replaced EGR with brand new Delco unit less than 1 year ago. Cleaned EGR, still comes and goes
- looked at coils, all have white numbers, so they're most likely originals, tested ohms across the posts (6.13 / 6.35 / 6.18)
- MAF was replaced about 2 years ago with Delco MAF
- wires were replaced with Delco wires by dealer about 2 years ago when LIM gaskets were done
- spark plugs are an unknown....I never did them and I don't think the dealer did them with the wires, they weren't on the bill
- control module is an unknown as well, but since coils appear original, it likely is original also
Am I taking the right steps in the right order? Input from the collective experience of the board is appreciated.
Thanks