Idle & Partial throttle issue

slytherin

New Member
Apr 5, 2004
702
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northeast ohio
I recently dropped out the 4.10's in favor of 3.55's as the cobra is turning into a DD unfortunately.

The issues started after the gear swap. I stopped to put gas in the stang filled up with premium as I had some spare scratch. What I am noticing 1st is a worse & lower surging idle upon initial startup it has gotten so bad in fact that the car is close to stalling(all idiot lights start to flicker).

Secondly, Lets say I am driving along at 45mph and just trying to maintain that speed in 4th at 2100 - 2200rpm. I can feel the car shudder/jerk and the exhaust doesn't sound right.

I can go and wrap the car out to triple digit speed and bring it back to sanity with no real noticeable problems but when I get back to that cruising/partial throttle speed I have about 30 seconds or less of normal feeling & sounding running. Then the afforementioned symptoms start up.

I was talking to my dad and he was saying maybe just disconnecting the battery for a while and making the computer reboot would cure it since it might have memory(does it?) of operating peramaters(sp) with 4.10's. My concern there is I will lose the check engine light codes I got a couple of times as I am about to get it in the shop(since I don't have access to a scanner) if I can't figure it out.

Any and all help greatly appreciated, Phil
 
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Yup, unhook the battery...

If the car still runs like crap, the codes will show back up. Oh and you really should invest in a cheap code scanner. I bought one for $20 or so at Wally World. It actually displays the numbers, so there are no counting beeps or lights or any of that BS.
 
Because we dont often use the term scanner, but you certainly do in Saab-world, I'll clarify (just in case there was uncertainty).

What we normally use a code READER. It simply retrieves stored codes.

A scanner (what the Saab Shop would likely use if you take the car in) is a good bit more expensive and can stream data in real time.

Phil, I might make sure that the IAC is clean and in working order (esp if you also have surging issues when turning on the A/C).

I have other ideas, but let's see about codes before I post up tangents.

Good luck.
 
slytherin said:
IAC ? since I dont have a diagram with me at work is that the one in the TB, or down the cold air intake by the MAF?
It's the cylinder lookin deal on the TB.

(The thing by the MAF is the IAT).

Good luck.
 
slytherin said:
IAC ? since I dont have a diagram with me at work is that the one in the TB, or down the cold air intake by the MAF?

It mounts to your throttle body, and has a 2 wire connector that pulls straight out from the top. It blocks access to the TPS sensor.

I would read the codes first, before resetting the computer. Then reset it, and see if the problem comes back. That way you know where the computer was leaning towards.
Scott
 
The gear swap and premium fuel don't really sound related to the idle, light throttle issue you describe. So I agree with the above about taking this one step at a time. But it might help to think through whether you have done anything else that might have triggered this condition. Any work under the hood? Any significant change in the weather? Any other symptoms?
 
Well I did the battery disconnect to no avail. So I took it in to my local repair shop. They have come to figure it out as my fairly new Pro-m MAF took a dump! Did I see on here a while ago that they got bought out or went under or something like that as I am not sure of what my options are with the defective part as far as maybe getting my $ back or a new part.
 
The new iteration of Pro M is PMAS (Professional Mass Air Systems).

DIdnt the MAF come up while retrieving codes?

Good luck.