[Bigdrumma22]

Just this morning as I was driving home from a friend's, I noticed the car was running rough off idle or when ever under load. I was originally thinking it had something to do with the clutch (hopefully not), but what I think makes the most sense is something to do with A/F or TPS. Reason is because I installed a C&L Plenum and BBK/Roush 75mm T/B last weekend with no adjustments. The T/B had a TPS already installed, so I just bolted it on and went. Ran fine for a week until today. I just got back from another test drive hoping it was only a morning fluke and it wasn't. There is no engine light on, or at least not yet. The car starts shaking a lot and you can see/feel the trans shifter shaking a lot which worries me. Idle is also a little erratic at times, but only by a couple hundred RPMs. What should be my first step in troubleshooting? TPS?? I'm about to check my Haynes manual for those symptoms, but please give me any suggestions to remedy this ASAP!!!

[BigJnSA]

if you havent disconnected the battery for 5 minutes, do that. simply could be just to relearn whats installed. id try that before anything else.

[Bigdrumma22]

Originally Posted by BigJnSA

if you havent disconnected the battery for 5 minutes, do that. simply could be just to relearn whats installed. id try that before anything else.

I thought of doing that, but it suprises me that it ran fine for the whole week... about 170 miles of driving without any problems. Also for everyone else, I think hesitation/stumbling could also be a good description. I'll try that first, but won't be touching it again until morning. What's next after that? Recheck all bolts for vacuum leaks??

[y2kGT]

Thats what i would do. Most of the time when you have a vacuum leak you throw a code, You should think about getting a tune soon though...

[Bigdrumma22]

Originally Posted by y2kGT

Thats what i would do. Most of the time when you have a vacuum leak you throw a code, You should think about getting a tune soon though...

Yeah, last time I had a vacuum leak, it threw a code, but it was a pretty large leak. I actually bought a used superchips tuner for $150 a couple weeks ago, but I haven't tried it yet, because I wanted the computer to relearn what it has on it first. I don't know if that makes a difference or not. I know a custom tune is probably more beneficial, but for the cost I want to give this one a shot first... and if not, it's still a code reader. I also have some kooks LTs and x pipe to go on in the next few months, so if anything, that's when I'll get a full on tune. As said before, I'm gonna try the battery in the morning. Thanks!

[y2kGT]

np..let us know what happens!

[stangfreak]

leave the battery off for more then 5 mins. try 15-30
also, to check the TPS, back probe it, you should be under 1 v at idel. (pref around .9v)
they are real sens. so could have been damaged in shipping.
just for starters.

[Bigdrumma22]

Originally Posted by stangfreak

leave the battery off for more then 5 mins. try 15-30
also, to check the TPS, back probe it, you should be under 1 v at idel. (pref around .9v)
they are real sens. so could have been damaged in shipping.
just for starters.

Well my thought was TPS before, but being that it ran perfectly fine for a week before it started acting up leads me to believe it's not that. If the battery doesn't work though, that's one of my next tests. I should've just done it when I installed the TB for safe measure, but being that it was installed on the TB already, I just hoped it was set already. Thanks for your input!

[keg65]

really bad gas?

[Bigdrumma22]

Originally Posted by keg65

really bad gas?

Like mileage or quality? I think you mean quality... and if that is what you mean, I always fill at the same station 95% of the time and haven't ever had a problem with bad gas. I guess that's a possibility as well.

[keg65]

did you fill up right before this started happening?

[Bigdrumma22]

Originally Posted by keg65

did you fill up right before this started happening?

I don't remember when I filled up, but it was 170 miles of driving before it happened.

[Bigdrumma22]

Ok, so I disconnected the negative cable this morning for 30 min. reconnected it and I still have the same problem. It doesn't matter if the positive is removed or not, correct?? When I got back from the drive I had my brother help me check the TPS. Reference voltage was good from the PCM, but at idle I have about 4V and at wide open I have 0.3V... does this mean they installed it backwards at the factory, or is that even possible? My Haynes manual says they are non adjustable, but I thought I read on here that it is... info please??? I do still have the factory TPS on the factory TB/Plenum assembly if necessary, but I don't want to install that wrong too if it comes down to it. Please any help is great as I need it to be running right tomorrow!!!

[Bigdrumma22]

Ok, well I think I broke the new TPS that came with the T/B so I put the stock one on there and I'm getting the same measurements (which are reverse of what Haynes says it should be). I disconnected the battery again, this time completely for about 30 min. I'm about to go start it right now, but how long does it take for the car to relearn? And if it doesn't get cured, where to next??

[Bigdrumma22]

Well it's still not driving right... so I don't know what to do... I'm frustrated!!!! And I'm going crazy!!!

[96greengt]

It almost sounds as if you may have a misfire but the PCM is not detecting it to set a MIL.

[Bigdrumma22]

Originally Posted by 96greengt

It almost sounds as if you may have a misfire but the PCM is not detecting it to set a MIL.

That is also another possibility I considered. I even had my dad drive it so he could see what I was talking about. Just sitting at idle though, it seems a lil' rough with a slight exhaust pop every now and then. Was like that when I got it though. Never thrown a code for that. You think it may have anything to do with the IAC? Don't think I have any TB cleaner handy, can I use anything else? I didn't pay attention to how dirty it may have been when I switched it over to the new plenum. Also, say it hasn't had a tune up in an estimated 2 years. Would you suggest doing one yet on 15K driving? Previous owner d_stang_j said he did a tune up less than a year before I got it and I've had it for a year. Sound at all like a fuel filter issue? Thanks a lot!

EDIT: Found this on another site concerning TB/Plenum swaps, let me know what you think!

"This is something that I have personal experience with. The combo that you have selected is perfect for the car. Don't look back. However, there are a lot of idle issues after doing the swap....no matter what combo you choose.

It seems that 99% of the problems are caused by one of four problems (in order of probability):

1 - The TPS gets damaged during the swap. It is sensitive and is VERY hard to remove. Consider buying a replacement ($25.00) and don't bother with the old one. It will save you time and aggrevation.

2 - Dirty IAC's that don't seem to bother the stock setup, rear their ugly head after the swap. As a precaution, clean the IAC while doing the swap. Why not...it will be off anyway. To clean, spray the inside liberally with intake cleaner that is marked on the can that it is approved for TB's. Let it soak for about 15+ minutes.

3 - Incorrect base idle setting. The TB will be set from the factory. But, sometimes, the setting is not right. It is sort of ludicrous to think that a company can set a idle screw on a TB from 1,000 + miles away and think they will get it correct all the time. If you are interested and run into a problem, I have a procedure for correcting the the base idle.

4 - In some cases you may need to replace the IAC. Ford has updated these a few times and most likely the one on your car is of the old design.

Hope this is useful to you."

[96greengt]

Plugs in these engines are (if OEM) are good to 100k miles in all reality. Possibly a coil problem for you. I have a new coil in my garage somewhere, they sell for about 60 bucks (depending on brand). Have you had it scanned for any codes lately? Just cuz the light is not on does not mean it does not have an issue.

Autozone does the scan for free and so do a few shops in town, you just need to find the coupon. My shop even ha a free scan... but we (as techs) hate doing anything for free.

[Bigdrumma22]

Originally Posted by 96greengt

Plugs in these engines are (if OEM) are good to 100k miles in all reality. Possibly a coil problem for you. I have a new coil in my garage somewhere, they sell for about 60 bucks (depending on brand). Have you had it scanned for any codes lately? Just cuz the light is not on does not mean it does not have an issue.

Autozone does the scan for free and so do a few shops in town, you just need to find the coupon. My shop even ha a free scan... but we (as techs) hate doing anything for free.

Well I have a superchips tuner (haven't used yet) which says it can scan for codes, should I try that? Also, when do you work, because I could probably swing by there during lunch because I'm close by at work assuming you don't have the same lunch schedule as me, 12-1. Could buy ya lunch if you solve my problem??

p.s. I used to do scans all the time working at Advance... I know it's annoying...

[96greengt]

Doing scanning at Advanced and being paid by the hour at least makes it bearable. I work on commission so it sux when we do it. My lunch is when I get time to go eat.