stephen18

So, after replacing the tps with an oem one, still getting power loss. its weird. Sometimes it feel quick, others it seems sluggish sometimes it starts sluggish, but then "clicks" into full power.

it shifts 1-2 sometimes way early, around 2500rpm. most times at idle, if i "blip" the gas quickly, but only a small amount, it will stall. doesnt die, just stall out for a half second or so.

i have now replaced: air filter, fuel filter, ecu(swapped with a different ecu, AND replaced caps on my old ecu), ignitors, tps, O2 sensors, ecu temp sensor, VAF(thought u was an "autozone rebuilt" one), coils, dizzy & caps, wires, plugs, tested the cam and crank sensors. have checked and replaced most vac hoses, tightened all clamps, replaced and cleaned all grounds, also added a few, new battery as well.


though i did find a slow coolant leak that was dripping on the harness...

stephen18

Any other ideas guys?

LScowboyLS

have you cleaned the throttle body and have you cleaned the AFM (MAF) with compressed air and/or a very soft chamois cloth? (do NOT use commercial MAF cleaners on pre-95 LS400)

python

iTrader: (4)

yes...take it to a shop that knows what the bleep they are doing,youve spent way too much money and time throwing parts at it..

quote from u
air filter, fuel filter, ecu(swapped with a different ecu, AND replaced caps on my old ecu), ignitors, tps, O2 sensors, ecu temp sensor, VAF(thought u was an "autozone rebuilt" one), coils, dizzy & caps, wires, plugs, tested the cam and crank sensors. have checked and replaced most vac hoses, tightened all clamps, replaced and cleaned all grounds, also added a few, new battery as well.
not sure what a dizzy is..but im sure it cost money. u never checked fuel pressure while driving? stop listening to people on the forums at this point..they arent the ones spending money.

stephen18

most of these parts needed to be done anyway. if i wanted to have someone else fix it, i would have taken it to a shop first. but as this is the only car i have, and i like to get my hands dirty, i want to do it myself, so i asked for some other opinions to try and help figure it out... thanks for being one of the least helpful forums i have been on. ( although some guys here are helpful)

stephen18

and dizzy = rotors

LScowboyLS

repeating:
still need these answers!


my kind of LS400 owner!

stephen18

Yes, i used compressed air to clean the maf, cleaning the TB was one of the first things i did to the car.

There are NO obd1 codes stored, and i have not gotten ANY since owning the car, except when the timing belt slipped i got a code 13. replaced the belt, clear the ecu, and no more codes. YES i did the belt right. used oem, read over the service manual, and used the lines on the belt, crank and cam gears to line it up. and since then have checked it to make sure its all aligned still about 3 times. I have even driven around with TE2 ans E2 shorted to use the "super sensitive diag mode" and no codes.

used an AEM wideband o2 and the afrs seemed okay to be, as i posted earlier in the thread.

i know the guy before me ran the car for several months with one bad cap... when i bought it the car was running on 4cyl. there is a post cat exhaust leak(at the cat/y-pipe gasket), but i am replacing the cats (stupid PO) within a few weeks.

it feels as it sometimes it cuts out for a second around 2200, if i floor it from a slow roll, but when it comes back in, its in second gear... but thats to only time i feel like it cuts out....

im about to just hook up my analog multimeter to every important sensor and watch them a few days at a time... this is baffeling

python

iTrader: (4)

most of the parts needed replacing anyways? highly doubtful
this is your only car and this thread is 4 months old?!!!!
this is the least helpful forum u have been on?...which means u r on others as well and no one seems to have the answer but yet u continue to throw more parts at it and ur car still isnt fixed.

awesome! good luck..you will need it

python

iTrader: (4)

btw this is how u diag a problem with these cars...working ur way to the ecm is the correct way to diag a car just like pure drifter said
https://www.clublexus.com/forums/sho...d.php?t=551125

LScowboyLS

just ignore the unhelpful Debbie Downer negative type folks, and we will eventually locate the problem, and in the meantime, you have learned a lot more about your LS400, and car repair, and gotten several critical maintenance items done!

python

iTrader: (4)

at some point common sense has to prevail

stephen18

yes things like the coils were weak according to resistance tests, ignitors i got free, vaf i cleaned with solvent and killed it (oops) plugs needed changed, o2 sensors were old and needed to be changed (they too have a recommended replacement interval) tps also tested out of spec, filters and the like should be changed when you buy a car anyway so you have a baseline to know when they need changed.. so really, what has NOT needed to be replaced? either as a preventive or proven out of spec/bad?

ingitors? i got them free and took 2 min to change
engine temp sensor? cheap, so who cares?


i am a service tech by trade (although a copier tech, the principle applies... electrical and mechanical systems interworking...) i have owned plenty other cars, most toyotas, and the other forums were not a lexus forum with the same issue, other forums for the other cars i have owned. i have worked on my own car for years so im not new to this,... i know how to test and diagnose things... i have all the oem service manuals, this issue is very intermittent and very hard to trace down, hence im asking for opinions here if someone else has had this or a similar issue...

this issues isnt so serious as i need to buy another car.. it just an annoyance at most.

also have already done all those suggestions in the link python made, thanks

python

iTrader: (4)

ok then..i could pick apart every single bit of ur reply but im not going to as it seems ur intent on continuing on the path of frustration...have u checked fuel pressure and volume while u r driving...? if u have and u have tested everything u need to then u have by process of elimination concluded its more than likely a ecm issue..also let me say throwing used parts (ignitors..temp sensor) is not the way forward unless u know for an absolute fact they are in good working order.

stephen18

ignitors were the only thing that was used and they came from my friends 93 ls that was wrecked.

no have not checked fuel pressure while driving, dont have a gauge that i can see while on the road. i will look into it, thanks