'98 T5M Idle and Power Issues

echase76 · Post by **echase76** » 02 Jan 2013, 09:03

Hi Folks, Over the last 3 weeks I have been having intermittent idle and power loss issues and I'm looking for any advice as to what might be going on with my car. I'll try to be as brief as possible, but hopefully give enough detail to be helpful.

-Car is at stage Zero
-zip tie "fix" on the MAF plug
-O2 sensors are new.
-car pulls hard at WOT

Power loss/idle issue symptoms:
-At start up (<10% of starts) the idle will almost drop to zero and almost cause the car to stall. This usually happens at start up and after a bit of working the gas pedal it will come back around. If I try to drive it before it stabilizes the car lacks power.

-The idle issue has happened a couple times when coming to a stop, but is usually is a start up issue.

-3 times now I have also felt a very quick power hiccup and momentary dead pedal. This is usually in 3rd gear under no load.

Recent 500+ mile trip (over the weekend):
-Drove 4 hours to NYC with no problem whatsoever until I hit traffic at the Holland tunnel. The idle started to get funky and bounce around, almost stalling at times. During an hour of stop and go traffic it happened maybe 7-10 times.

-Get in the Holland tunnel and suddenly the car is idling at 1500-2000 rpm!! Could this be due to all the exhaust and low O2 content in the air?

-Out of the tunnel and the RPMs hang high for a bit, but the car sorts itself out before I get to Brooklyn and park.

-Park for 2 days, drive home 4 hours Sunday with no issue and car has behaved ever since

Thoughts:
I'm almost positive I DON'T have a vacuum leak, but will revisit the idea if that is the consensus. At first I thought the Fuel Pump relay, but now I think the MAF might be dying. Could it be something related to Idle control valve?

Post by **Ozark Lee** » 02 Jan 2013, 11:03

Cleaning the IAC valve doesn't really cost anything and it can't hurt anything. One of mine came to me with similar problems and that, along with a bunch of other stuff, got it straightened out. In my case the IAC was all gunked up inside.

A flaky fuel pump relay will cause the car to just die, I don't think that is the problem.

Is this at all temperature dependent?

...Lee

echase76 · Post by **echase76** » 02 Jan 2013, 11:29

It generally happens in a cold start situation, but does not happen all the time. I even tried waiting 2 cold nights and it started just fine. The NYC trip was a hot engine after driving 4 hours.

Someone mentioned ECT as a possibility.

I'll clean the IAC this weekend.

Wanted to add. MPG has been steady and temp gage has been solid middle through all this.

echase76 · Post by **echase76** » 02 Jan 2013, 19:21

So my wife had the idle/power issue today.

Starting the car warm the idle surged for her between almost stalling and 1500. It stabilized and she drove off. A bit later while in gear, but foot off the gas, it had another power hiccup.

I'm still planning to start with the IAC and go from there looking for Vac leaks, fuel issues and I've been told to check ECT.

echase76 · Post by **echase76** » 05 Jan 2013, 14:10

Got the IAC and TB cleaned today. The IAC was definitely a bit gunked up so hopefully that was the issue.

This was an easy job and I just followed the instructions that I found on this site. TB is also easy to clean and a no brainer if you already have the IAC off. All told it took me less than an 1.5 hours and half the project was done with my 3 year old son.

So far so good, but will report back after a few days as my issue has been intermittent.

echase76 · Post by **echase76** » 08 Jan 2013, 19:01

Well Crap! The car is back to its old tricks after a couple of good days.

It is having the idle issues, but this time when warm. Bouncing around between 500 and 1000. Usually happens after a bit of driving or stop and go traffic, but not all the time (one a day maybe). Seems that a few good highway pulls clears things right up for a bit.

Tomorrow I get a new upper IAC hose from the dealer (old one was rock hard), but don't expect it to help.

Suspecting a vac leak now, but no problems at WOT. What else could it be? MAF? ECT (temp gage is rock solid at 3:00)?

echase76 · Post by **echase76** » 10 Jan 2013, 20:18

Yeah, I know this thread is stale and boring. Whatever, I'm keeping it going in case someone that has similar issues is searching later.

Cleaned the MAF last night. Definitely dirty, had some black buildup on the leading edge of the sensor. Ran really well after the cleaning and idle was rock solid after the computer relearned. Continued to run strong today without any issues. I suspect that the dirty MAF was the main culprit.

I would highly recommend cleaning your IAC and MAF if you have not done so before. Very easy and should really be part of stage 0.

echase76 · Post by **echase76** » 19 Jan 2013, 19:09

Back with an update. Things finally got bad enough tonight to throw a p0171 (Lean). The car was stumbling fairly consistently at low throttle and was bouncing around at idle. Even stalled out on me once, but only took a couple tries to start back up.

Based on what I have done below I'm suspecting the MAF is bad or maybe the FPR is on its way out.

I also think I have a small exhaust leak at the flange, but nothing big.

My symptoms are a lot like this with less stalling. http://volvospeed.com/vs_forum/topic/14 ... -stalling/

Thoughts before I throw more parts at this car???

Post by **jtp** » 19 Jan 2013, 20:26

Have you checked hard for vacuum leaks? The throttle body spray method is pretty effective.

echase76 · Post by **echase76** » 19 Jan 2013, 21:04

Yeah, tried that and got nothing. Plan to try again after tonight's issues. Will try to get smoke tested this week if I can't find anything.

A bit concerned that I'm only getting 18hg vac. Boost is good and holds.