355 Idle RPM dropping sometimes down to 650 for a sec or two while driving

Well I don't think this part of the convo will help with the car technical issues for others but if there are any issues with drinking I am sure there are lot of offerings from rehabs and such. As of weight - a gym?

 

Thanks Ian It's a part of my last name.

 

The yellow paint must be factory. Mine has it too.

Heres a shot of mine off 97 gated spider. Looks like this is Bosch part is used in many applications so should be able to source reasonably if needed.

I ran some cleaner through it and cycled it a bit then blew it out with the compressor. Will try later today.

Much needed quiet time garage therapy this morning after a rough week.

 

I bought 2 new ones from Porsche reseller cost like $85 each. Then I set them to 0 ohms and reset the ECU. The part is 20 years old just replace it, it's condition will not improve with time.

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Actual Bosch units are looking pricey and harder to find but available. There are plentiful aftermarket units at all price points if you cross reference.

 

I found the oem Bosch units in a Bosch box l on eBay from Porsche reseller, but that was 12 months ago. Same ones were used on 964 I believe. Same with coils and igniters.
Perhaps market demand is drying supply up. Never use knockoffs. They royally suck if they even work. The knock off mags are essentially non functional.

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So I hoped this was the silver bullet. Cheap and easy. Appeared to be resolved through a spirited 30 min drive to my favorite ethanol free station. Filled up, on the return trip did it a few times. I'll probably replace the TPS anyway sometime soon.

 

I used to have idle issues off and on.....the car would run one way one day and the next would run differently. I used to stop at times for a half hour and cut power and then let it relearn to clear up the issue....a week later same thing.....I installed the gold connector kit and never had that problem again. Its now been 12 years and still runs perfect and no there is no corrosion on the contacts due to dissimilar metals.

 

BTW when you remove and replace the TPS the resistance will be different as there is room to twist it in the bolt holes. Definitely reset the ECU and see if that solves it as it relearns if it is the TPS which I suspect not.

Also try cleaning the MAF with MAF sensor cleaner then reset the ECU as well. Both worth a shot!

 

One thing I've yet to do but haven't is clean the throttle plates really good. Primarily because I'm dreading removal and reinstall the plenum. I know its possible but looks like a fight and test of patience to do. Unless I get really motivated that may need to wait till I drop the cradle or fall/winter.

 

+1 on the gold kit. I did the same & experienced the same.

Not sure if the kit is still available, but it’s worth doing IMO.

 

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Those are available everywhere and actually really easy to find. I mean you can order them from RockAuto I believe.

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$55.79

https://shop.advanceautoparts.com/p/bosch-bosch-throttle-position-sensor-c701225550bos/10809877-p?c3ch=PLA&c3nid=10809877-P&adtype=pla&product_channel=online&store_code=&gclid=Cj0KCQjwwLKFBhDPARIsAPzPi-IZ37d-CMy3BeRvJcS9twQGPuwJnJ4dXq9PfXMOa8o-nM5dI7sSCSQaAoPuEALw_wcB&gclsrc=aw.ds

 

Thats the 0 280 122 001 which are dirt cheap and everywhere. The specified unit is 0 280 122 004. Not sure the difference but 004 has unicorn tears in it if you must have bosch.

I've been trying to find a data sheet on them to compare but no joy.

Looks like 001 was used on 2.7 cars as well as many others. Where the 004 was only a handful of F, P, and Saab.

 

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=+bosch+0280122004&_sacat=0

 

I have one on the way. Will report back.

 

I don't thin that is problem. No way with just a bobble time to time at low rpm, nah. I'd start with new O2 sensors. If its still there I'd try cam phase sensor. If its still there I suspect its the MAF. The MAF reading wrong wont throw a code it just wont read right. Most of these electronic bits are as such, they slowly degrade they wont throw a code unless its dead. Could the the igniters I supose.

Incidentally I traced a weird issue sort of like that back to a loose fuel line on my in tank fuel pump.

Many of these cars in this era have oddities like that. Many people follow the if it aint broke don't fix it mantra. Then when the cars have odd behaviors they just say what do you expect it an old car. Nah that's bulls**t, mine idles and drives like its 1990. Did not when I bought it yet everyone said it was amazing, I don't accept bobbled at idle or stumble here and there as "its an old Italian car what do you expect bs"

Possible items include come to mind (I replaced each item all and saw effects of each one)
MAF -Most likely
Cam Position sensors - Most likely
Cam Phase sensors - Most likely
Igniters-Medium likely
Coils -Medium likely
Fuel pump - less likely
FPRs - less likely
IAC's- less likely
TPS- less likely

 

I've got new O2s laying here ready to go. They are pain to get at with leverage. Pinned up against the frame with the cable its tough to get a crows foot on. Any tricks regarding getting to them to save the kids from new vocabulary?

 

DO NOT get antisieze on the probe tip, you'll be replacing them again but not before you rule out O2 sensors since you JUST replaced them and chasing your tail. Take a wild guess how I know that.

Try an O2 socket or one of these
https://www.harborfreight.com/3-8-eighth-inch-offset-oxygen-sensor-wrench-97177.html?cid=paid_google|||97177&utm_source=google&utm_medium=cpc&utm_campaign=&utm_content=&gclid=Cj0KCQjwwLKFBhDPARIsAPzPi-K_jg9H0jcnlj3CCLycXAP_X0Q6c46QdMXop4QETz0Hhj1GZtlI1MYaApE1EALw_wcB


Reset the ECU when done with any of it.

 

Thats what i meant by crows foot linked above. Slang for o2 socket. Going through the wheel well easiest?

I've been picking away at it over the last year. New coils, O2 etc.. Agree as is most would think its fine and 99% timenit is but I know it can be better.

 

Ok makes sense yes crows foot wrench is a specific tool not the same but you got the gist.
For 348 through wheel is easiest, but I just grind through from the top and bottom depending on the side. Not worth the effort to pull the wheel liners. O2 ground straps are a good idea as well.

 

I can confirm the TPS isn't the issue . But I have one if ever needed! So I got that going for me.... which is nice.