devanm87

when i put my car in nuetral it verrry slowly revs up. pedal to the floor barely does anything but after a few minutes of climbing rpms it hit around 5000 rpms then the engine sounded fine and pedal responded as it should. but when i let off pedal abit and dropped it below 3500 rpms it went really sluggish again. barely climbing rpms till it hit around 5000 again. when i put the car in drive it has no power and only moves slightly. replaced the fuel filter because that was easy and still the same. after reading up a little i think it may be a bad catalytic converter or o2 sensor? any ideas for when i take it to a shop? i dont know anything about my car haha.

rogers2014

ok, i'm still a beginner but i"ll try. I have a few vaccum leaks (this affects our cars ALOT) check and you will know if you have vaccum leaks just feel, how i found mines out was spraying seafoam spray (which i recommend you doing) in the intake, when we did that we saw some spray come out one of the hoses so i have a vaccum leak, check your tps (throttle position sensor) and i also reccomend you doing this (which i have to do still) luckily someone made a vid:


also clean your throttle body with seafoam as stated....will eat up alot of that carbon, check your oil and fluid levels as well my car is still running sluggish but by doing these little things, it will help you determine what else is wrong. also check plugs, and air filter let me know how it works out

Ali SC3

iTrader: (10)

what kind of car/engine do you have first? also what maintenance have you done to it.
If you have the v8 I would tell you to check your coilpacks.

rogers2014

Hey ali, i have a question regarding that, where are the coilpacks located? and how would i detemine if i need to change them i have the 1uz v8 engine still learning!

devanm87

i have a 92 sc400 4.0 litre v8. no maintenance has been done for a while because it was parked for a year or so

chingpo05

iTrader: (2)

run a compression check and look for any check engine lights, if theyre present then pull the codes

devanm87

well after reading a few forum topics on this site i decided to check the coil packs because others have had the same sort of issues. i disconnected 1 coil pack and the engine fired and almost started up. disconnected the other coil pack and no fire at all so i am assuming the coil pack on my drivers side may be screwed. ordered a new coil pack for 91 bux will replace it tomorrow. wish me luck haha :P

Ali SC3

iTrader: (10)

its a definite possibility, it happens all the time on 400's thats why I asked which engine.
take a look at the cap and rotor also, chances are they will need to be replaces on both sides if they havent in a while. that should give it back some of the power it had before.

Ali SC3

iTrader: (10)

they are the ones marked C

devanm87

well the new coil pack did not work. took it to a shop and they said 1 of my catalytic converters was messed up because it was reddish looking and was heating up bad. took it to a muffler shop and removed both cats- because they do not check emissions where i live.. still no fix.. played around with the throttle positioning sensors and still no effect.. next was going to see if there are vacuum leaks.. could a bad cat cause vacuum leaks? another trip to the shop i guess.. thank you everyone for the help and will get back here when i found out what it is.

V8drummer

iTrader: (5)

You sure you hooked the new coil pack up correctly? The catalytic converter was red because raw fuel is dumping into them. Could also be a bad ECU. Do you smell a lot of raw fuel?

I'd also verify that you have spark at each cylinder.

vangb2

iTrader: (2)

If I didn't know what I was doing. I can end up saving a lot of money by paying someone that know what the heck they are doing to find the problems instead of shooting in the dark.

Have some reputable shop diagnose and fix this.

Ali SC3

iTrader: (10)

yeah if you killed you catylitic converter you are running very rich, removing them wont fix anything.
did you replace the right coilpack? there are 2 of them on your engine.
you either have a bad ecu or an ignition problem with those symptoms.

rogers2014

Hey ali, forgot to thank you for the diagram of where the coilpacks are located! really appreciate the help!

As for the guy who has his car running rough... don't worry you will fix the problem, its better you learn this way then to go and get someone to fix it for you!!! but u will get it fixed, all of us here at club lex are like brothers and sisters lol

devanm87

yea car has been in the shop for a week. they checked my spark plugs and wires and its all good, 1 of my distributors was loose shaking around so they replaced it and still nothing apparently.. now im thinking of checking the fuel ecu or mayb the wires connecting the coil pack? blaaahhhhh and i believe i replaced the right coil pack because when i tested them i disconnected the drivers side one and the engine fired but reaaally rough then i reconnected that one and disconnected the coil pack on the left side and it would not fire at all but the starter was trying so i replaced the driver side coil pack and nothing.. btw i think it was on this forum where i learned to diagnose the coil pack. so thats why i am now thinking it may be the wires connecting it.. going to talk to the guys at the shop tomorrow because i just got the phone call... dam the shop is costin me money !! >.<