Thread: irratic idle in drive while warm

Hello and thanks for reading

I got a little problem that seems to be getting worse.
while the car is in drive and the car is at operating temp it seems to misfire then jump up the RPMs. there is about a 300 RPM fluctuation when it happens. this only happens while its warmed up and only at idle while in drive then it hesitates a little while accelerating once over 1200 RPMs it doesn't do it anymore.
list of things I did the 2 weeks before this started happening:
changed plugs and wires
oil change
drove to Wisconsin 4 tanks of gas
noticed slush in radiator removed 1/2 gallon coolant added 1/2 gallon straight anti freeze (it was cold and the car sat the whole time I was there)
drove back to Texas 5 tanks of gas (made a side trip) last fill up right before I parked the car for the night

next day is when it started doing it
I have checked the wires and plugs. I was going to check the coils today but it's raining. it did pop a SES light but it went off when I started the car up again and hasn't been back on

SO what you think it is?
coils?
FPR?
coolant issue?
trans issue?
operator idiocy?

any ideas?

thanks for reading
Jake

yesterday christmas day I drained the coolant and put in fresh 50/50 mix. Now it does the same thing in park and it's worse in drive but still no SES. Soon as I find my multimeter I'm going to test the coils.
Anyone know where I put my multimeter???

tested the FPR it seems fine still cant find my multimeter
BUT I had a can of carb and choke cleaner and half a can of MAF cleaner now I got half a can of carb cleaner and 1/4 can of MAF cleaner.
once it got done smoking its idling better.
I will seafoam it tomorrow
hopefully I can find my multimeter before then or I will just buy another

threw code P0300
hopefully it's bad gas still got 5/8s of a tank left going to run that down to under 1/8 and then fill it up after I replace the fuel filter

the same thing happened to me right before i 'blew a head gasket'.. only it didnt actually blow the head gasket.. its just compromised the head gasket and intake gasket... you might be in for a fun engine project.. but hopefully you got lucky and it is something different

I'm still hoping its bad fuel. I will find out today I'm going to drive it till I'm almost outa fuel then change the fuel filter and fill up again.

hmmmmmm sounds better now that I have 3/4 of new gas in there and I reset the ecm.

wonder how pissed the apartment complex will get if I seafoam it in the parking lot

Originally Posted by Lord4play

hmmmmmm sounds better now that I have 3/4 of new gas in there and I reset the ecm.

wonder how pissed the apartment complex will get if I seafoam it in the parking lot

I barely get any white smoke when I Seafoam my car.

Originally Posted by 01gpgt01

You gotta dump it in the vac port under the blower and stall it out. Let it sit for awhile. She will smoke lol

it's a gt don't have the top swap done yet haven't seafoamed it in over 10k miles. and had some stuff done to it since then.

like:
CAI
cat and rez removed ubend removed
180 stat
reprogrammed
that and I was doing 80-90 the whole way back from wisconsin maybe I built up so junk I don't know yet

but I loved the way the car pulled in the 10 degree Wisconsin weather

also not sure if this is related but I noticed 24-26mpg going up there and 28-30 on the way back down with 400 pounds more stuff in the car....maybe the car was just happy it was going to thaw out

oh I'm going to seafoam it at pepboys tomorrow when I go into work

the FPR looks stock but I'm not sure how to test it other then pull off the line and see if it leaks and it doesn't at least not that I can see

I seafoamed it today I also have 12 miles on the new tank of gas. It still has the SES light on and it still misfires just not as bad as it was 2 days ago it seems to slowly be getting better but I think I would like to change out the FPR just for he hell of it

we had a nice little pow wow at work about my car 4 mechanics and 4 parts guys and I think we may have narrowed it down to a few things

FPR
ignition module
fuel pump
REALLY REALLY bad gas
and....
I'm imagining the whole thing and so is everybody that listens to the car

heres a new one .......a buzzing noise coming from behind the dash. and I noticed duct tape on a plug for the abs under the hood....


this is really starting to bother me.... I will be replacing plugs and wires this next week even though they only have 4000 miles on them

all senors in the TB have been cleaned and will be replacing senors also sometime soon

..... I think the head gasket is leaking....but it may just be left over seafoam I will wait for the engine to cool down and go check it again

If you have an internal coolant leak it would cause misfires at low speeds but you'd also see lots of white smoke.

no smoke, I check the coolant every 2 days still the same, and the oil is still right at the top of the full mark hasn't moved that I can tell

um yeah ok??? well I went and did laundry about 1 1/2 miles away from my house...the car did that same thing all the way there.... while I was there I found the half used bottle of MAF cleaner.... so I decided to do that to pass the time..

well.... done with laundry I started the car back up....SES light went out ....no misfires.... ran like it should till I got into the parking lot of my apartment... then it started misfiring again.....still no SES light

so I'm still lost....

unplug the maf and see if it gets better.

if it does, then the MAF is bad.