Car not idling properly (wants to stall)

[141]

I own an 05 corolla sportivo with a CES cold air intake with a K&N pod filter, CES headers and custom exhaust. At one point in time the previous owner had played around with the PFC and had some success with it but enevitably returned it to stock. I bought this car second hand in November of 2011 and havent had any issues with it until now. I have been having a lot of issues with idle for about a month now. One day just pulled off a set of lights (not hard at all, bit of granny driving), and i noticed a lack of power i then put foot back onto clutch revved the engine a little then released clutch and all was good for about two days. Then car started to spit and would not hold a steady idle was ranging from 500 to 2000 and so i let it go to see what would happen and then it went down to 500RPM and then just stalled. I started car and it was all good for about an hour or so but when i was driving and released the accelerator a little you would hear a bang from the exhaust pipe kinda like a back fire. I looked on these forums and i found that majority of the causes are dirty MAF sensor, dirty ISCV and also that the pod filter having too much oil would cause this. I didnt do the last service on the pod filter but seeing as it has been almost 7 months of me owning the car and no issues i kinda had my doubts about it. Anyway i cleaned the MAF sensor as that is what everyone had said was the main culprit and it seemed to work for about a week until car wanted to stall again. So then i went and cleaned it again along witht he ISCV and the air filter and also changed the oil and oil filter just incase there was dirty oil coming in from the intake. The oil had been in car for about 5000-7500kms and car had been fairly thrashed yet oil still looked good. Anyway after cleaning all of these using the step by step for cleanign ISCV the car worked fine for about a week again until it happened again. So starting to get frustrated i took it to a toyota service and parts and had it looked over. What they found was that the piping had been moved and no coolant was going to the ISCV so they reconnected it the way it "should" be and also replaced a gasket in the ISCV. (Previous owner had bypassed throttle body in an attempt to keep the air entering engine as cool as possible). Again car worked fine for a week or two until it wanted to stall again and i had to drive around with one foot on clutch one on acclerator and hand on the hand brake. I took it back to the service and parts and he said he would have another look so he cleaned the ISCV again and did all the checks and said it was working fine. It did work fine for the rest of that day and then it happened again. I havent tried anything since and that was done friday just gone. It only ever seems to happen when engine is warm. I tried the other day hitting lift when i had the issue and it seemed to resolve the issue so next time it happened i hit lift again but this time no success. I have no idea what else to do and i dont want to hand money over to the dealer if they dont know what is happeneing either. This is my second car and is my first car with mods. Im hoping in future to learn more to add more mods but wish to solve this issue first.

I have talked to a few people and they have given me advice to check coil pack, the earthing wires and that prehaps in an unlikely case it could be an O2 sensor. I havent checked the earthing wires yet as i havent had time but was wondering if anyone else has had same kind of issue and has resolved it. Any help would be appreciated.

Sorry for massive post

Sam

[Kenshin X]

spark plugs have been changed since u got the car?

[141]

No i havent yet but i spoke to the previous owner and they were changed at 70000km's and car is now at 99 901 :P so i wouldnt have thought it be necessary?

[Evo7]

I have had the same problem, most likely a faulty throttle body, the ISCV sensor would be messed up.

(bit of background) when I upgraded to TRD, i had the throttle body provided, was fine for ages, then started to fluctuate idle (search for this)

I found out the previous owner had the same problem, now i NEVER had this issue with my old throttle body, so i changed it back to my old one and success :D

so thinking this could be the problem.

Evo

[141]

(bit of background) when I upgraded to TRD, i had the throttle body provided, was fine for ages, then started to fluctuate idle (search for this)

I found out the previous owner had the same problem, now i NEVER had this issue with my old throttle body, so i changed it back to my old one and success :D

so thinking this could be the problem.

Evo

Sorry but what did you upgrade to TRD? and are you suggesting i get a new throttle body?

[stock]

best thing to do is get it hooked up to a computer to diagnose it. but most likely it will have something to do with the TB

[141]

Toyota hooked it up and they found a few codes that came back the first time but apparently they didnt mean anything and there were none the second time they hooked it up.

[Evo7]

yes, get a new replacement/ second hand throttle body and see if it resolves your problems.

Evo

[141]

Okay, thanks for that evan

[CHA54]

it will not be the actual throttle body. If anything it would be related to the TPS but that would show up on Toyota's scan tool.

I'd be swapping the stock intake back onto it first, but I'm guessing you didn't get that with the car? Does your CES intake have the 2.75" modification at the MAF section so it reads correctly?

What method did you use to clean the MAF?

Over time the ISCV's can wear when run without the coolant lines connected, it's difficult to test them properly without an aftermarket test rig to monitor the valve position and response through the PWM range.

[141]

it will not be the actual throttle body. If anything it would be related to the TPS but that would show up on Toyota's scan tool.

I'd be swapping the stock intake back onto it first, but I'm guessing you didn't get that with the car? Does your CES intake have the 2.75" modification at the MAF section so it reads correctly?

What method did you use to clean the MAF?

Over time the ISCV's can wear when run without the coolant lines connected, it's difficult to test them properly without an aftermarket test rig to monitor the valve position and response through the PWM range.

I actually did get the stock airbox and a bit of piping not sure if it is all of it though. and the CES has an outside diameter of 3" I'm not familiar with CES so they may have done something tricky internally to keep the outside looking "pretty" but from what i have seen when cleaning the MAF i doubt it.

I just used the method that was on the workshop and just used contact cleaner. Toyota servicing also had a look at it and gave it a clean.

The "tests" on the end of the How to Clean an ISCV workshop that Superdave put up didnt seem to work for me but when i took it to Toyota they said that it did everything it was supposed to when they did testing, however i didnt ask what their testing involved. Im not sure what a PWM range is, but would toyota not have the appropriate equipment to have tested this aswell?

[Evo7]

I still think its to do with the ISCV

Evo

[141]

it will not be the actual throttle body. If anything it would be related to the TPS but that would show up on Toyota's scan tool.

I'd be swapping the stock intake back onto it first, but I'm guessing you didn't get that with the car? Does your CES intake have the 2.75" modification at the MAF section so it reads correctly?

What method did you use to clean the MAF?

Over time the ISCV's can wear when run without the coolant lines connected, it's difficult to test them properly without an aftermarket test rig to monitor the valve position and response through the PWM range.

I actually did get the stock airbox and a bit of piping not sure if it is all of it though. and the CES has an outside diameter of 3" I'm not familiar with CES so they may have done something tricky internally to keep the outside looking "pretty" but from what i have seen when cleaning the MAF i doubt it.

I just used the method that was on the workshop and just used contact cleaner. Toyota servicing also had a look at it and gave it a clean.

The "tests" on the end of the How to Clean an ISCV workshop that Superdave put up didnt seem to work for me but when i took it to Toyota they said that it did everything it was supposed to when they did testing, however i didnt ask what their testing involved. Im not sure what a PWM range is, but would toyota not have the appropriate equipment to have tested this aswell?

[141]

Sorry for the double post. Anyway I'll look into the ISCV, I'm meant to be studying for uni exams at the moment haha just trying to get an idea of all the issues it could be so i can eliminate them once i'm on holidays in two weeks. All ideas and opinions are welcome.