tssiems

Hi,

I've run into a problem that is very weird and I'm wondering if anyone else has had the issue or the solution. I've read quite a few posts that get close to my issue, but mine seems to be different. Specifics, 125K miles on the engine, non-turbo. Yesterday, the car started just fine and after about 10 minutes of highway driving I had to stop for road construction. During this time, the idle would vary between 1000 and 2000rpm's and make a weird fluttering noise out of the tailpipes. After getting moving again, I took the next exit and the car stalled at the first stop light, but would restart right away. I took the car home and put into the garage. Today I started the car and it took right off and I drove around town for at leat 1/2 hour, engine got throughly warmed up and I had absolutely no issue with high rpm idle, nor stalling. When I got home, I shut off the engine and then in about 30 seconds restarted it. The rpm's went to about 3k on the start, stayted there for about 10 seconds (it's done this since I've had it), then droppped to 500, bounced back to 2000-2500, then to 1500 and then that weird noise from the tailpipes again. I'm suspecting something electrical and/or the EGR valve, but that's in painful place to get to. I can't hear any vacuum leaks and I replaced many of the vacuum hoses a couple of years back when I changed the pulsation dampner. I also had used contact cleaner on the TPS connector and BAC valve, hoping that the problem was just a connection issue. I'm pretty competent under the hood, but reluctant to start 'fixing' things w/o knowing what the problem may be. I haven't tried to set the TPS sensor, but if anyone has solved my issue with that approach, I'm not opposed to trying it. It just seems so weird that it worked perfectly fine for 1/2 hour then has this issue.

Thanks for any and all feedback.

Doug

vaughnc

When was the last full tuneup including plugs, wires, oil filter, air filter, fuel filter, etc? Do you have the original exhaust & original catalytic converters on there, or have your replaced them with a free-flowing exhaust? Are the electrical grounds on the engine & battery terminals/wires all original (aka internal wire corrosion)??

Sideways7

iTrader: (7)

You can hear vac leaks over your exhaust? I wish I could do that....
Anyway, I would go ahead and at least check the TPS. Its a pretty simple thing to check if you can use a multimeter. A bad TPS can def cause idle problems, though I have no idea about the fluttering noise. Your problem doesn't really sound like a vac leak to me, but I could be wrong.

stevie1020

sounds like it almost time for a rebuild

tssiems

Thanks for the feedback guys, I appreciate the insights. I do keep the car in pretty good condition and I'd say the plugs have maybe 10K on them, new wires just last year along with a new 02 sensor, which I changed when I replaced the pulsation dampner. I could buy into a rebuild, if the problem were more consistent. I ran the car on Tuesday for almost an hour w/o having a single issue, started right up, idled rock solid at 800rpms and plenty of power. I got back home with it, shutoff the engine and then restarted in about 30 seconds. I immediately had the idle issue then, down to 500, bounce to 1500, back to 500, etc. I shutdown again, restarted and then it would idle just fine! I'm thinking the problem is electrical in nature and will check electrical grounds, etc. I have looked over the TPS setting routine only I can't find any adjustment on my car (non-turbo), like I see in the writeup for setting the TPS with the two lights and/or a DMM. I'll use my DMM and take some readings against it next time I run the car. In response to an earlier question, the car still has all of it's original exhaust. I've never driven the car in MN winters, so it's rust free and in really good shape inside and out, hence my wanting to resolve this issue. I've changed the oil ever 2K miles since I've had the car, so I was hoping that it's not an engine issue. I'm wondering if any soft of ignition problem can cause this idle condition or if it's strictly a air/fuel issue. Maybe what I'm hearing from the exhaust is losing a rotor (ignition wise), though it doesn't seem like the exhaust is more 'gassy' or anything like that. I'll try to attach a timing light next time out too or my Fluke 88 which has an inductive pickup.

If this additional information trigger any thoughts for someone, just let me know, I'd appreciate it!

Thanks, Doug