VB2NC

I posted a similar question on Benzworld, so I thought I'd try here as well. Under hard acceleration, the car will cut out for about 1/2 a second and then immediately regain full power. The problem is intermittent in nature. As a matter of routine maintenance/to cure low idle, I have recently replaced the coils, plugs, wires, MAF, crank position sensor, thermostat and coolant temp sensor. Yet the problem persists.

It feels like a fuel cut-off gets tripped for a split second, but I'm not sure if that's a likely scenario on these cars.

DropTop430

i had the same issue couple of years ago... it was an oxygen sensor near the Catalytic Converter....when i floored it ... it wouldnt go anywhere ....it would take long to speed up .. anyways i remember being sensor that ensures precise voltage to the engine's emission control computer.... hope that helps

mint

Have you scanned for codes?

DropTop430 -- how'd you know it was your O2 sensors? Codes or just tested the voltage?

VB2NC

Sorry for being out of touch for a while. Twinsin, no codes at all thus far. Droptop, I've been doing some searches which implicate the Throttle Position Sensor/Pedal Position Sensor sending intermittent signals to the ECU. I ordered an OEM TPS that I will install tomorrow. If that is for naught, I'll test the O2 sensors as you suggest.

Thanks for the suggestions, and I'll post the results.

DropTop430

Tested it and wasn't getting any voltage at all and replaced it when I had my caytalic converters replaced ...

Redw20855amg

Check fuel pressure and the MAF

isaac2238

I had a similar issue with loosing power intermittently when flooring it, my mechanic replaced the air filter, fixed the problem straight away

Good luck


Isaac

VB2NC

OK, I changed the TPS over the weekend with an OES Hella unit. We've since driven a couple hundred miles without a single stumble. Time will tell if the problem is fully cured, but we're clearly on the right track.

VB2NC

Here's the latest update. I've driven about 500 miles since changing the TPS (and fuel filter) and the car has stumbled 6 times. One was a light stumble with a warm engine under full throttle acceleration. The rest were hard stumbles when accelerating moderately on a cold engine. I suppose O2 sensors are the next thing to test. Any other ideas?

dlbehrns

I assume TPS is transmission position sensor????? where is that located? did you replace the CPS/crankshafts position sensor?

VB2NC

TPS is the Throttle Position Sensor located on the driver's side behind the engine firewall. I have indeed replaced the CPS as well.

bobbyjo9

As sugested earlier, have you checked your airfilter yet?

Jonaska

I'm having a similar issue. When I accelerate thru flooring it. The kick down works, the car starts to accelerate then suddenly around 5500 rpm cuts of all power for a second or more. WTF? I’m thinking catalytic converter, but no error codes except something about the ”load limiter being active”.
Since I’ve got this behavior I replaced the fuel filter, spark plugs, air filter and the MAF without any luck.

Jeffery Bergen

same problem...im embarrassed to share with you guys but here it goes...

some punk kid on the free way was testing my patience as he was taunting me to run him...so i finally bit to his silliness. wasnt helping my buddy was pushing me to see if i still have it..etc...long story short as i pressed the throttle full speed it basically accelerated than bogged out then accelerated... like it woke up or caught its breath...sadly to say i was smoked by a mazda3 due to this...hopefully you find a solution. ill be following this real close man..

Jonaska

A matter of fact, cough is a very accurate description of the behavior!
I feel with you Jeffery.
My car accelerates fine with half pedal pressure. Could it be the fuel pump not making enough pressure? Could a faulty oxygen sensor be a reason?

Jeffery Bergen

i was thinking that too. but im starting to think it was my after market intake along with plugs that need to be replaced. im going to replace fuel pump,filter,plugs+wires,revert back to stock air box, change serpatine+other belts and pulley, might port the exhaust manifold and drop in custom headers from the v8 cut to fit and change the stock intake. o2 sensors all of them, and who knows my maf may dirty as well.

this is a long laundry list which may take a while. ill update you guys once im complete to see if this happens after all the replacements..

also it can be the rev limiter as well. or ecu so it can be alot of things going on...

tomtomtomtom

My bad/failing fuel pump was starving the engine under hard acceleration....check the fuel pressure up front/rails...only a suggestion.
No problem after pump replacement (do the filter at same time)

Jonaska

I've changed the fuel pump yesterday. Unfortunately, no effect. When I was test driving I disconnected the MAF and the problem went away immediately! Could it be a faulty MAF?

Jonaska

How are things going Jeff? Have you cured your problem?
I'm still struggling. I bought a OBD2 scanner which can view live data. The one thing I see is when the problem occurs the fuelsys value goes from CL to OL-DRIVE. Any ideas?
I’ve also tested the car without the air filter, that did make it go worse all the way with the problem still in place.
But when I disconnected the MAF (with air filter in place) the car did go smoothly without the problem. Although it did loose a couple of horses…
I’ve just changed the MAF a couple of months ago and do not want buy another just to test.
One thing I’ve noticed is that the MAF does jerk I bit where it sits. So I’m going to try with some silicone to make it air tight around it’s connections.
Has anyone any other ideas on what I could check?

ArnettsBenz

Don't Know it its the same for 430's and 320's but I have a similiar problem with my 430, took it to my MB mech and he said the transmission sensor that shifts the tranny trough gears is out of sync and needs to be replaced. Not something that will ruin the tranny, but he said the anything at WOT if will bog out for 1/2 second to a second and then kick back in. He also said MB has updated the part 4 times and is now close to $1k to replace. So car is fine for regular driving but cant mash on it without the delay... Might be that...

Jonaska

Interesting! I have automatic transmission and was thinking the same thing...
I will investigate and get back…

sirswift93

I have the same problem with my 2001 CLK320 Cab. If does feel like the tranny; if you let up just a bit on the accelerator and them mash it down it feels like its lost its place. Does anyone have a part number for the tranny sensor? Maybe buying a used one at a scrap yard wouldn't be so bad.

dlbehrns

When you say behind the firewall are you saying it is in the engine compartment or inside the car up under the pedals? Having a hard time visualizing it. TIA.

sirswift93

It's right in front of the brake booster. You will see the throttle cable connected to it. Newer models are behind the gas peddle.

edwardelkhatib

Wow I only just started getting this problem and it started since the cold weather when I used the W position on the gear shift in the snow. Now since I have returned the rocker switch back to the S position the tranny does strange things?