Hey guys,

To start off, my car is a 93 sc400 with 130k. My car was driving perfectly until one night, I noticed it hesitated a little bit when i stepped on the gas. I didn't pay any attention to it, until later that morning, when I started it up again. It sounded horrible and did not want to accelerate at all. I traced it to one of the ignition coils and got it replaced. Everything was smooth and running, until the next morning. It happened again. I went ahead and replaced the other coil as well. no help. I have since replaced air filter and the rubber hose on the intake (it was cracked), cleaned the throttle body, and checked all spark plugs. everything seems fine. The engine will idle smooth and normal. But once I take it for a drive...Absolutely no acceleration. The car is an automatic, but it feels like I'm driving in 5th gear, when I should be in first....

 

TPS maybe. Sounds like your car runs smooth and idles fine but the problem is only when you try to give it throttle. maybe the TPS has gone bad. im no mechanic but just to thought to hopefully help with your diagnosis.

 

My SC is doing the exact same thing your describing your SC is doing. It turns out I have an exhaust leak somewhere in the piping.

"The simplest solution is usually the right one."

Edit: I just thought of something, smell your exhaust while idling. Does it smell really rich? If it does, then I think it would be the MAF sensor.

Good Luck!

 

This same exact thing happened to my friend (Redphoinex) a couple of months ago. Turned out to be his MAF. If you know someone that has a 400 borrow theirs and try it in yours

 

Thanks guys, I will look for the exhaust leak and try the MAF. I was searching through the forum and noticed that some people disconnected their MAF sensor, and the car ran perfectly. how does that work? when i disconnected my sensor, it still ran like crap. maybe it is the problem.

 

some cars will switch to a different map and "assume" what the maf "should" be reading. It'll rely on the TPS, RPM, Speed, AIT, and a few other sensors and take an educated guess on what the MAF is seeing, even though it's not there anymore.

So with that being said, if the maf is dirty or fubar, it'll still have some kind of reading, and the ecu will actually take that reading and go from there. So if there isn't any reading at all, it'll just assume. Of course it usually doesn't work for OBD-I cars.

Does it sound like it's missing at all? When I first did a tune up on my car (new plugs, and wires, pretty much most of the ignition system) I ended up chewing one of my plug wires because I didn't route it correct, so the cam gear and timing belt teamed up on my number 8 plug wire, and the wire lost that fight.

 

um, this might sound dumb, but could you guys tell me how to take the MAF off to change it or clean it. I have tried searching, but nothing really shows up. I took a part the little black box on top of the air box, but I dont think that's the sensor.

 

anyone with any ideas? I am getting so frustrated with this freakin car.

 

there's some wiring that comes out of the distributor covers on the forward side of the engine. check to make sure the serpentine belt isn't rubbing those and creating a short. That is the wiring for the cam position sensor. also check your crank position sensor wiring at the bottom near the crank on the port side (left facing front). Common issues that create what you're talking about.

 

Hey, an update with my problem... so it wasn't an exhaust leak. What happened was that the "hotwire" in the maf sensor got contaminated and was give off readings to the ecu

I bought some maf cleaner from autozone, and sprayed the ****** out of it. It helped out ALOT!

To take it off, ur probably going to have to take off the headlight. Theres a couple tutorials on here if you search. Or try planetsoarer.com or intellexual.net

Edit- The maf sensor is the device right behind the airbox.

 

UPDATE:: I finally got my car back up and running. I did a complete tune up on it. I changed out all plugs, wires, rotors ,coils, and fluids. so happy i got it done and got my baby back. Thanks for all the help guys!!!!

 

Mine has been doing the same thing. My check engine light came on and its reading two codes. The TCS and the Knock Sensor. I just got the TCS replaced it helped a little but its still hesitating pretty bad. So it could be this MAF?