I just put a new PCM in my car and sometimes I will be driving it and ill press the clutch in or put it in Nut. and the rpm will stay right around 1900-2000, but as soon as the car comes to a complete stop it drops again.If i am in 6th at 1500 sometimes it will go up to 2k when i take it out of gear and it will bob around 1900 and 2k then drop after a few seconds. I dont know what it is .

 

Well my car does pritty much the same thing and it has the original pcm. Except mine will go to about 2000 when I press the clutch then it will huvver around 1500 untill my car comes to a complete stop. IMO I would say it was nothing but then again I would get some more opinions.

 

I have had the same damn problem for a long time now. I think it's the iac but I haven't gotten around to pulling it out - I have a feeling I'll have to take the tb off.. I just can't get access to the dang thing.

I run true duals 3" w/o mufflers.. and coasting up to a light with the car running at 2,000 rpms is just rediculuous.. get's old real fast.

Anyways, if anyone has solved this problem please shoot me an e-mail..

Thanks

 

Same problem here. Holds about 2000 rpm's until I come to a stop. Just started it after I got my PCMForless tuning. Thinking maybe its something in the tune.

 

I have a 95 Z and mine does the same thing you are describing about 50% of the time. I also heard it is normal but dont know for sure.

 

started after my pcm forless tuning as well.

 

I also had a PCMforless tune about the time this started happening.. this seems a little strange to be a coincidence. I'll e-mail them and send them a link to this page - hopefully they'll be able to give us some insight.. they've always had really great customer service in the past. I'm sure if this problem is somehow related to their program they'd be more then willing to correct it.

 

most of that problem is the iac follower programming, or could be a sticking iac.

try pouring some sea foam or wd-40 in the iac port in the throttle body to see if it clears anything up.

gm programmed the iac to stay open while you are driving down the road so when you shift, it will keep the rpms up and not cause lurchy gear changes, for the less experienced people. Try leaving your car in gear till you get below 1500 rpm coming up to a stop and see if your car will idle normal. if so, try and start driving that way, my 97 would do that all the time till I started idling down at a stop, then throwing it in neutral to wait the light out, mentions something about it in the owner's manual.

 

Sorry guys, I know I said I'd send off the e-mail the other day but I just got around to doing it - internet explorer and outlook express have been causing some catastrophic failures on my comp and that's been hindering my cz28.com and e-mail usage the past couple days My bud majoring in comp science came over and said "wow.. hmm.. that's bad.. really really bad." I think I have a temporary remedy anyway.. at least I managed to send the e-mail off a few minutes ago.. here's what it said:

Bryan,
I've been running one of your mail order tunes and have been having what I thought was an unrelated idle problem that started about the time I installed the new pcm. Well I've been browsing the camaroz28 boards and have stumbled across a couple other people with the same problem and they have all had pcm tuning done by pcmforless recently also - I recognize that this could just be some bizarre coincidence but thought I should at least ask you if it is possible that the idle problem is related to your tuning. I do know that you can control how fast the idle drops (in steps) as the car coasts to a stop (thus allowing you to keep the idle up to maintain power accessories such as brakes as the car is coasting).

Anyway, I would very much appreciate it if you could check out the thread, look into the problem, and let us know what you find.

Here is the thread:
http://web.camaross.com/forums/showt...91#post1753091

Thank you,

William Hauser



sean1997ws6: this is not a normal thing.. I'm certain the car never did this stock. I've had the loud **** exhaust for a while and I distinctly remember a time when the car did not have this annoying problem.

I do understand what you're saying about the elevated idle generating sufficient vaccum to run power accessories (namely brakes) as you're out of gear coasting at a high speed.. in fact I mentioned that point exactly in my letter to Bryan... but what the car is doing now is something different.. something that it definately never used to do and definately should not be doing.

 

My car does the same thing, but for a different reason. When I installed, heads/cam/intake I reprogrammed the IAC throttle follower so that the car had perfect driving manners, even when coasting to a stop. But then I developed a vacuum leak. It's an internal vacuum leak caused by the intake manifold being warped and not sealing to the heads well. So the intake gasket leaks. It mainly leaks when the throttle blades are closed (high vacuum) and it causes the idle to be too high when coasting, but once the car stops, the PCM lowers the rpms to the Target Idle speed by closing the IAC valve further.

So I'd say it's either your programming, dirty/broken IAC, or a vacuum leak.

 

Any of you guys also have the abs inop light come on along with this, mine comes one right away.

 

OMG , this is WAYYYYYYY to much to be a coincidence !!! I just bought my car a couple of weeks ago and the guy I bought the car from said he had just got his PCM back from PCMs for less . And guess what ? My damn car does ALL of these things decribed here ... My ABS inop light comes on after startup , runs sick pig rich and smokes at full throttle , and idles high for a second or two ... I have sent Bryan 3 emails , NONE returned ! This is a PROBLEM !!!!!!!!!!

 

I don't have an abs inop light or a check engine light.. my mileage has been seriously suffering however even on the interstate w/cruise on - which would eliminate the possibility of the idle problem being the sole cause though I think it's certainly part of my poor fuel economy which is absolutely terrible around town where the idle level is relevant.. it may also be bad o2's however but I don't get any CEL which would come on if o2's weren't working correctly... the fuel economy could well be something else but I really am convinced that the pcm programming is responsible for my almost constant 2,000 idle (only idles normally if car is completely stopped).. I'll let yall know what I find when I check for a vaccum leak and faulty iac which are the other possible sources of the problem IMO. Unfortunately the car is down now and will be down for a while (clutch work).. I'll be gone until wednesday night skiing in lake tahoe so the car won't see any work untill probably two or three weeks from now

I just dunno.. I'm still waiting on Bryan to respond to this thread.. we'll see if he can shed any light on the subject.

 

Hi Guys,
One thing I have added a few years back to my programs is cutting the IAC counts on the cammed cars to keep the idles from hanging high when rolling to a stop. Some fo your cars I may have to cut it down even more. If some of you want I can send some test PCM's out to test this with and check the results. Also, sometimes you need to adjust the throttle body as well to help. Some of the aftermarket TB's and even stock ones need the throttle blades adjusted closed a little more as the IAC's may be bottomed out and just can't close up enough to bring the idle down. Try turning the throttle stop set screw in a little and see if that helps. On the cars with cams the extra air the cam is pulling in at idle is the reason I have to cut the IAC counts down.
I haven't seen the ABS issue with this before, as the ABS is a seperate computer.
The most common cause of poor mileage I see is bad or lazy O2 sensors or melted wiring going to them. Also, any time the o2 wires are spliced to lengthen them I see this as well.
Guys, email me your names and I can look over your programs and make sure that update with the lower IAC counts is already in your program and if the throttle body set screw adjustment doesn't help I can try new things.
thanks,
bryan
PS- Sorry for the delayed reply I was dyno tuning yesterday all day.

 

Billy, I haven't had any emails from you, are you sending it to programmer@pcmforless.com or my old email address? I am VERY good at trying to return all emails
Thanks,
Bryan