Stumbling engine?

Hi guys my 3.5 intrigue seems to stumble while driving it. It feels as it the engine is stumbling or loses power for less than a second and it will do this a few times in a row and will be fine for awhile and then repeat itself.

This can happen while cruising, slow acceleration or at a stop light. I don't really notice it under harder acceleration.

When it does happen i do notice that the rpm's drop a very slight bit.

Any ideas and help would be appreciated. Thanks

do a search on this forum for "CKP Sensor" or crankshaft position sensor. Yours is bad and when it switches from bank1 to to the bad bank2 you get the temporary stall until it switches back to the one that works (2 sensors on one unit, one sensor is bad one works) Stall will happen around 1/4 temp. May see the SES light up temporarily when the tempory stall happens (look for ODB2 code).

Discount the crank relearn procedure. That mechanic didn't know what he was talking about and nobody does it. Save yourself the cash and the sensor was about $70 for the GM part. Starter needs to be moved to get to the CKP sensor = takes about 1 hour to do the swap = buy the quality GM CKP sensor unless you enjoy taking out the starter multiple times. Disconnect battery first.

my answer before was too short: The stumbling will turn into a stall if the revs drop below ~600rpm. Put into neutral and restart -even if the car is moving. I would do this for awhile hoping that eventually the service engine soon or service vehicle soon light goes on (OBD2 code).

#1. You get a OBD2 code (scanner). Eventually a crankshaft or camshaft position sensor will eventually throw a code. This helps narrow down things considerably. Could be a MAF sensor. Cylinder misfire for sparkplug or the sparkplug boot (should throw a code and tell what cylinder).

#2. No SES, No SVS light = no OBD2 code:
Could be all of the above, plus things like the A/C clutch causing drag especially with the A/C on in summer. Transmission sensors. Fuel pressure regulator and MAF sensor usually do not throw codes.

If the spark plugs were changed you should 100% change the spark plug boots ($3-5 each). The spark follows the spring in the boot and there is diaelectric grease in there that acts as insulation. When you pull the old boots out -they stick/are brittle and tend to crack. =you get stuttering (with poor power under load) that can cause a stall.

I would keep driving it and learn how to quickly restart in neutral if it stalls. Note when the stalls occur in a notebook and maybe from this info you can infer what the problem is. Search the Intrigue forum from the Intrigue forum home page on the topics above.

=these cars are old now and parts will start to fail. May want to get the full Service manual or look into AllDataDiy. My car is stalling at idle after I changed the original plugs with NGK and put in new plug boots + fixed an exhaust hole. Great power and everything but will stall once driving and warm at idle.
The positive is that the stalling and stuttering is a rather minor driveability issue and the parts to correct it are cheap. Taking the time to find-out and fix the issue is the hard part. Learn how to restart in neutral if it stalls and search these forums for situations like yours to look into your problem. As a last effort a GM Tech2 scan ($100-200) may be able to isolate the problem.

-corroded battery connections
-engine air filter
-MAF (mass-air-flow sensor)
-FPR (fuel pressure regulator -usually will leak fuel when bad, fuel smell by engine top right)
-plugs/boots if over 100k miles and not replaced (is a coil pack off somewhat from reassembly)
-drag on engine at idle causing engine to drop below 600rpm and stall.

These cars are only worth <$3000 (many $1000 or less with issues -search Craigslist) now. You bought it and it is yours to have and to hold until death do you part.

Cleong - buy the Oldsmobile Intrigue Service manual set $50 or less on Ebay. The 1999 edition has info for the 3.8 and 3.5 LX5 engines and has 3 books instead of 2. -Many of these service manual sets on ebay and most are less than $25. I believe I paid 3x that and get the GM books and not the dvd scam editions.

Alldatadiy.com can even be better for trouble shooting at $27 a year. Flowcharts etc. You can buy the service manual set for the cost of one year of alldatadiy now.

I used to have Alldatadiy.com, but with the service manual set and this forum I figure I don't need it and haven't used it in 5+ years.