Car won't run after plug change, help please?
05-04-09, 05:33 PM
#18
Driver School Candidate
Thread Starter
The car will run now, the alternator has been changed, the coil for #6 has been changed and the plugs are now iridium. However, the car is still throwing P0306-Cylinder 6 Misfire, and now P1128 and running generally bad. Still idles low and feels like it's missing in the lower rpm's. Is this TCM lock? Intermittently the throttle will go out and you have to push it to the floor to get the car to move. APPS sensor? TPS sensor? Dirty throttle body? How do I know for sure if the sensors are bad? Any help would be greatly appreciated. What about adjusting the TPS?
05-05-09, 06:14 AM
#19
MAF maybe. I was getting similar symptoms with my MAF failing. Do you have a friend or someone that has a GS like yours that you can swap out mafs to check. That is how I finally got to the bottom of my problem. My car would also fire up, then stall. If I keep starting it with slight throttle, it would sort of idle., then when it would warm up, it would idle really low. I thought it was the ECT, engine coolant temp guage, because it threw a code for that once. But in the end, the maf fixed everything.
05-05-09, 06:59 AM
#21
Driver School Candidate
MAF could be dirty too?
I have no problems running single electrode plugs in mine...in fact it runs better, more power, and better mileage with the single electrode vs. doubles! I changed out the plugs right when I bought mine and it had singles in it, I replaced with double electrodes. My mileage dropped ~2mpg, it ran like crap in the mornings when I'd start it, and lacked any real power. I changed back to single electrode plugs and most of those problems vanished!
As for your current situation...not sure what to say other than a dirty MAF or possibly you mis-connected wires or misplaced a pack?
When we swapped cams on my mustang 2 years ago we assumed the longest plug wire would go to the plug furthest away from the engine (cylinder 8). This stupid assumption led us to take the top end of the engine off 3 more times to try figure out why it was running like crap and misfiring like hell. Come to find out the 2nd longest wire went to cylinder 8 and the longest went to 7...stupid little things can cause pretty big headaches so check on stuff like that too!
I have no problems running single electrode plugs in mine...in fact it runs better, more power, and better mileage with the single electrode vs. doubles! I changed out the plugs right when I bought mine and it had singles in it, I replaced with double electrodes. My mileage dropped ~2mpg, it ran like crap in the mornings when I'd start it, and lacked any real power. I changed back to single electrode plugs and most of those problems vanished!
As for your current situation...not sure what to say other than a dirty MAF or possibly you mis-connected wires or misplaced a pack?
When we swapped cams on my mustang 2 years ago we assumed the longest plug wire would go to the plug furthest away from the engine (cylinder 8). This stupid assumption led us to take the top end of the engine off 3 more times to try figure out why it was running like crap and misfiring like hell. Come to find out the 2nd longest wire went to cylinder 8 and the longest went to 7...stupid little things can cause pretty big headaches so check on stuff like that too!
05-05-09, 11:25 AM
#22
Ok, I talked to a buddy of mine that is a head tech at lexus. He said that you are to never clean the MAF with anything other than cleaner designed specifically for MAFs. If you used some other BS like CRC or something that did not say MAF safe, you just killed your MAF. You are also not supposed to spray in there like its the end of the world, that element is very sensative, and will get messed up easy with the liquid flow, if the spray tube is too close to the element.
05-06-09, 09:50 AM
#23
Driver School Candidate
Thread Starter
Ok, well I don't have an intake and I haven't attempted to clean nor even touch the maf. I didn't even unhook it during the plug change. Do you know if the cleaner you speak of is available at auto parts stores or is it only available through Lexus?
05-07-09, 07:06 AM
#24
No autoparts stores should have it. It is supposed to clearly say MAF Safe. Big letters. Although I doubt that this is what the problem is, it is worth a try. Get Throttle body cleaner too. Might as well clean that as well.
Now, check that all those hoses are connected to the intake plumbing. We have 2 plus a sensor that just clicks in on the 430's. I have this feeling that you have unmetered air intake flow somewhere.
I was getting random missfire code, cyc6 misfire, cyl3, cyl2, and cyl1 misfire. That was due to having the SRT intake on the car without the SRT ECU. The only reason why that happened, is because the my messed up MAF could not meter the air at all. That is why your symptom seems to be the same. Look a new MAF cost me $140, but only because I have a buddy at lexus. I think everyone gets them for $172. See if you can get a buddy to come by and swap MAFs with you to test. Nothing will happen to either MAF. Two screws, one connector, and you are golden. Take off the connector, unclip the filter cover, unscrew the clamp on the filter cover tube, take off the entire cover with the maf attached to it. It will be easier to take off the MAF this way.
Also, the ECT sensor. Enging coolant temp sensor. I paid $40 for it. Turns out that is responsible for sending the MAF a corrected startup to warmup reading, wich flashes the ECU with a corresponding map. What I suggest, is start up the car, and let it idle till it reaches proper temp. See if it runs better when that happens. If it does, I would recommend changing that as well.
PCV valve. I would not even think about changing this one as well. It's like $8. Mine wouldn't lock properly if blowing into it. Constantly leaking air.
I have plugs if you want. Proper Denso Iridium ones. I used them for about 2k miles. I had a similar problem as you. So I purchased these, then thought maybe they were bad, I mean seriously, I had misfire too. Problem didn't go away, so I purchased another set. Problem still didn't go away. If you want my old ones, $3 and you pay shipping.
By the way, my car feels insane now. I am telling you, I must have purchased it this way initially, with a starting to go bad MAF. My whip feels like a proper 300hp car now. Peels out like a ****, on oversized Pilot Sports Summers on IS350 Rims. Car is smooth as butter now, shifts, downshifts everything is dope.
Now, check that all those hoses are connected to the intake plumbing. We have 2 plus a sensor that just clicks in on the 430's. I have this feeling that you have unmetered air intake flow somewhere.
I was getting random missfire code, cyc6 misfire, cyl3, cyl2, and cyl1 misfire. That was due to having the SRT intake on the car without the SRT ECU. The only reason why that happened, is because the my messed up MAF could not meter the air at all. That is why your symptom seems to be the same. Look a new MAF cost me $140, but only because I have a buddy at lexus. I think everyone gets them for $172. See if you can get a buddy to come by and swap MAFs with you to test. Nothing will happen to either MAF. Two screws, one connector, and you are golden. Take off the connector, unclip the filter cover, unscrew the clamp on the filter cover tube, take off the entire cover with the maf attached to it. It will be easier to take off the MAF this way.
Also, the ECT sensor. Enging coolant temp sensor. I paid $40 for it. Turns out that is responsible for sending the MAF a corrected startup to warmup reading, wich flashes the ECU with a corresponding map. What I suggest, is start up the car, and let it idle till it reaches proper temp. See if it runs better when that happens. If it does, I would recommend changing that as well.
PCV valve. I would not even think about changing this one as well. It's like $8. Mine wouldn't lock properly if blowing into it. Constantly leaking air.
I have plugs if you want. Proper Denso Iridium ones. I used them for about 2k miles. I had a similar problem as you. So I purchased these, then thought maybe they were bad, I mean seriously, I had misfire too. Problem didn't go away, so I purchased another set. Problem still didn't go away. If you want my old ones, $3 and you pay shipping.
By the way, my car feels insane now. I am telling you, I must have purchased it this way initially, with a starting to go bad MAF. My whip feels like a proper 300hp car now. Peels out like a ****, on oversized Pilot Sports Summers on IS350 Rims. Car is smooth as butter now, shifts, downshifts everything is dope.
07-19-20, 07:21 AM
#26
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98 Lexus GS400 I changed the plugs and it won't start.
No autoparts stores should have it. It is supposed to clearly say MAF Safe. Big letters. Although I doubt that this is what the problem is, it is worth a try. Get Throttle body cleaner too. Might as well clean that as well.
Now, check that all those hoses are connected to the intake plumbing. We have 2 plus a sensor that just clicks in on the 430's. I have this feeling that you have unmetered air intake flow somewhere.
I was getting random missfire code, cyc6 misfire, cyl3, cyl2, and cyl1 misfire. That was due to having the SRT intake on the car without the SRT ECU. The only reason why that happened, is because the my messed up MAF could not meter the air at all. That is why your symptom seems to be the same. Look a new MAF cost me $140, but only because I have a buddy at lexus. I think everyone gets them for $172. See if you can get a buddy to come by and swap MAFs with you to test. Nothing will happen to either MAF. Two screws, one connector, and you are golden. Take off the connector, unclip the filter cover, unscrew the clamp on the filter cover tube, take off the entire cover with the maf attached to it. It will be easier to take off the MAF this way.
Also, the ECT sensor. Enging coolant temp sensor. I paid $40 for it. Turns out that is responsible for sending the MAF a corrected startup to warmup reading, wich flashes the ECU with a corresponding map. What I suggest, is start up the car, and let it idle till it reaches proper temp. See if it runs better when that happens. If it does, I would recommend changing that as well.
PCV valve. I would not even think about changing this one as well. It's like $8. Mine wouldn't lock properly if blowing into it. Constantly leaking air.
I have plugs if you want. Proper Denso Iridium ones. I used them for about 2k miles. I had a similar problem as you. So I purchased these, then thought maybe they were bad, I mean seriously, I had misfire too. Problem didn't go away, so I purchased another set. Problem still didn't go away. If you want my old ones, $3 and you pay shipping.
By the way, my car feels insane now. I am telling you, I must have purchased it this way initially, with a starting to go bad MAF. My whip feels like a proper 300hp car now. Peels out like a ****, on oversized Pilot Sports Summers on IS350 Rims. Car is smooth as butter now, shifts, downshifts everything is dope.
Now, check that all those hoses are connected to the intake plumbing. We have 2 plus a sensor that just clicks in on the 430's. I have this feeling that you have unmetered air intake flow somewhere.
I was getting random missfire code, cyc6 misfire, cyl3, cyl2, and cyl1 misfire. That was due to having the SRT intake on the car without the SRT ECU. The only reason why that happened, is because the my messed up MAF could not meter the air at all. That is why your symptom seems to be the same. Look a new MAF cost me $140, but only because I have a buddy at lexus. I think everyone gets them for $172. See if you can get a buddy to come by and swap MAFs with you to test. Nothing will happen to either MAF. Two screws, one connector, and you are golden. Take off the connector, unclip the filter cover, unscrew the clamp on the filter cover tube, take off the entire cover with the maf attached to it. It will be easier to take off the MAF this way.
Also, the ECT sensor. Enging coolant temp sensor. I paid $40 for it. Turns out that is responsible for sending the MAF a corrected startup to warmup reading, wich flashes the ECU with a corresponding map. What I suggest, is start up the car, and let it idle till it reaches proper temp. See if it runs better when that happens. If it does, I would recommend changing that as well.
PCV valve. I would not even think about changing this one as well. It's like $8. Mine wouldn't lock properly if blowing into it. Constantly leaking air.
I have plugs if you want. Proper Denso Iridium ones. I used them for about 2k miles. I had a similar problem as you. So I purchased these, then thought maybe they were bad, I mean seriously, I had misfire too. Problem didn't go away, so I purchased another set. Problem still didn't go away. If you want my old ones, $3 and you pay shipping.
By the way, my car feels insane now. I am telling you, I must have purchased it this way initially, with a starting to go bad MAF. My whip feels like a proper 300hp car now. Peels out like a ****, on oversized Pilot Sports Summers on IS350 Rims. Car is smooth as butter now, shifts, downshifts everything is dope.
So my Lexus GS400 will not start after I change the plugs and a couple torn coil pack boots. Any advice on that please? Thank you also I'm looking for maybe someone in Missouri that has a parts car be willing to heart out four point me to the right direction or get some cheaper parts. Thank you
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noblesenga
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