[skeeter123]

2000 Alero 3.4L V6 with 120K miles, stalls while driving down Interstate. I bought this car used in 2005 (had 52K miles, seller claimed good maintenance schedule), ran good until recently. ~ one month ago had problem with engine overheating, turned out to be warped coolant reservoir (where cap screws on), so that it wouldn’t hold pressure. New cap didn’t fix it. Had to replace the reservoir itself. In the process, I flushed/drained the coolant system several times, switching from Dexcool to Prestone, replaced the ECT (which wasn’t bad after all), switched to a 180-deg thermostat (temp read a notch below half-scale), and patted myself on the back. Then, about 1 week later, this new problem came up. Forgive the long narrative but I think it may be relevant. I assured my wife the car was A-OK and sent her off on a long trip. She got about 120 miles and called me to say the car stalled, while driving normally on the interstate. I was all over the temp thing, but she said it was just fine (below half-way mark). But when she re-started the car, it seemed OK so she went on. Another 100 miles, dies on Interstate, at 70 mph, engine just stops running. Pull over, wait 1-2 minutes, restarted acted fine. I met her & swapped cars. I got about 100 miles, going 76 mph with cruise control on, engine RPMs drop from 2100 to about 1000 for 3-4 seconds, then zero. Coast off to the side of the road, turn off ignition, try to restart, after 2-3 tries it starts up and everything seems A-OK. Same again at about 70 mile intervals, with or without cruise control, all the way home. The time seems to be important, it’s not how many times you try to restart, just wait a full 1 ½ minutes and it starts right up. At no time did the SES or other fault lights come on. Autozone code reader showed no codes. Also, I got 29 mpg on this trip home, including these stalling incidents. Lots of things must be OK for that to be happening. I did find the short U-shaped vacuum hose on the EGR solenoid (which goes from EGR to the plastic vacuum pipe) looked OK when engine off, but would be all sucked in on itself when the engine was running. I replaced it with a piece of vacuum hose Autozone guy gave me for free. I put some fuel injector cleaner in the tank (on sale, and I’m getting desperate), no noticeable effect. More desperate, I put in a new 195-deg thermostat. Operating temp now reads right at half-scale. But it stalled out after only 30 miles, and again 15 miles after that. But this a.m. I got all the way to work (30 miles) without stalling. I think the higher temp thermostat makes problem happen sooner, or maybe it’s just progressing on its own. Is the 180-deg thermostat a good idea? Does it require PCM re-programmming for lower fan turn-on times? Problem never happens on start up or when cold. Putting it in neutral and trying to re-start while coasting doesn’t work. You have to wait the 1-2 minutes. I read this forum and appreciate the advice. I haven’t done the FPR “suck test” yet but I did pop the vacuum line off the FPR and it didn’t smell/look like any gas was leaking. I cranked it with the vacuum line off, didn’t see/smell any gas. I bought this car intending to let my daughter drive it into the ground, so my maintenance approach wasn’t much more than oil&filter and wait till something really broke before fixing it. Glad I got 68K miles off it, but I’d like to not have to buy a new/used car right now. So, I’ve bought the following parts to install: fuel filter, front O2 sensor, 41-940 plugs, set of new spark plug wires. Any other 100K-mile maintenance items I should replace (that hopefully will solve this prob)? The plug wires are definitely the originals, I suspect plugs and fuel filter are also orig. I don’t know, but suspect its never had the LIM-gasket replaced (I groan when reading about all the probs with these Alero’s) but there doesn’t seem to be any coolant in the oil or vice-versa. Serpentine belt looks OK, may/may not be original. Only other thing is that the horn switch in the steering wheel broke, horn works when locking car, but not when pressing on the steering wheel. There’s a spring-loaded slide mechanism in the steering column (behind the air bag) that got all twisted up, I removed the bent-up contact plate, but its possible that the wire may still be loose up in there. This is my first post, any suggestions are greatly appreciated. I am pretty mechanically inclined, prefer to do what I can myself (time permitting) but need this car to get well and don’t want to have it apart for days or weeks at a time. Thanks.