I have no idea what's going on but maybe fellow org members can help me out here. When im in 2nd gear around 2k I punch it and theres like a lag the engine picks up but doesn't seem like its going to the wheels then after a sec it picks up and goes. On the highway I was in 5th gear cruising, I floored it just to get around a car and it felt like my engine was rocking back and forth like studdering, but I have polyurethane/NEW oem mounts. Here is a list of things that were done to my car:

-New PCV
-Fresh oil change
-3 new 02 sensors
-New fuel pressure regulator
-Mitsubishi coil packs with 50k on them
-Full tune up with platinum plugs done about 12k ago
-New 97 TB, the only problem was the arm that turns the TPS, I think this may be at fault.
-MEVI manifold completed clean inside
-EGR was cleaned
-MASS airflow sensor was cleaned 2k ago
-NEW axles and New tires

Now the knock sensor was changed about 3-4 years ago. I only use 93 octane and the time my brother had it he used 91-93. I did a compression test and I am above 185 in each cylinder. Vac test shows my engine is completely sound. I have 109k, 5 speed. Im either guessing its a knock sensor or just my clutch is really bad and it slips when I floor it.

 

sounds like your clutch is going, same symptoms when mine went. does the RPM need go up a little, comes down, then picks back up again. feels like hardcore lag when you punch it in 4th or 5th, but odnest do it in first, 2nd or 3rd? then its the clutch

 

I hate it, it feels like 50 hp was just lost. If I hit it @ 4k in 1st gear my tires would let loose, now It doesn't do that. When I hit 2nd and 3rd there is just a massive power loss It doesn't grab hard into the next gear its just continues to rev up more from the last gear. When I let go of the gas and rehit it then it fully catches into the next gear. Im guessing If im fully into a gear and punch it, that it might just be slipping therefore I get this automatic delay.

 

i get the same thing man. i've been posting this for a while now (ever since i got the car) all the parts are 10k old [ KS, pcv, plugs ] i've cleaned the maf, iacv, oilchange every 3.5k, coilpacks tested out fine ; been trying to keep up with everything, but i still get that annoying lag between 2 and 2.5k the engine makes growling noises, but the wheels are not following.

 

sounds more like your TPS, if your clutch was slipping you'd notice the engine revving up without you going anywhere. Also, pull your injector connectors and coil pack connectors and look for corrosion. Also, do you have an intake? When I put on my intake, I developed a small lag in that same region, could be part of your problem. And finally, of course, clean your TB

 

I had a problem with my tps due to my new TB. Here's the story, I bought this TB off an org member for 15 bucks it was in perfect shape, Mine was dirty and the cable holder was turning a nasty brown/black color. So I did the swap in 10 min, noticed that arm that turns the tps sensor was diff from my old one to the new one. The new one has 2 bars that turn the switch my old one had like an L shape arm that moves the switch. I did my best and Turned the tps so that the engine would idle and If I moved it away from the TB plate the engine would rev up. So I thought that was fixed.. I could get a new TPS sensor from a 97 maxima. Im sure it will plug in the same connector.

 

Isn't 50HP is a little much for just a TPS problem? To me it sounds like the latter you mentioned: coil or could also be a massive timing problem. Does the car idle OK?

 

The car idles at 650-750, Then tends to dip at 500 and kinda vibrates, I do have polyurethane mounts so the vibration is there. Coils packs have 50k on them, they are the mistusbishi ones. A full tune-up was done 10k ago. I did a compression test last weekend, plugs looked great compression results were great, timing is correct, the vac. test would have shown late timing. It could be a TPS problem. Its just lag on the low-end. When Im around 4k It usually tends to pick up on power. If I punch it in 2nd gear @ 2k there is a lag once it hits 3k it picks up somewhat faster then feels like it just dipped in power then picks up a lot faster. It's strange..

 

Just put your old TPS sensor on the newer TB if you think that is an issue.

 

weird, sounds like a vacuum leak...that would do the drop to 500 at idle and shake thing... But I think you said you checked that. maybe your mevi is stuck open and you are losing alot of bottom end?? I really don't know.

 

Knock Sensor.

 

Well i have a problem like that with my 91 5.0. I brought it to the shop and found out it was running to lean. Still havnt fixed it yet, no dinero.

 

If you cleaned or did something else to the MAF check the plug on it again.....It should click twice when you put it back on...That was my solution when i put my intake on, I had similar problems....

 

I have a similar problem. At first the car shakes at stops and was worse with the ac on. the code eas cylinder 1 misfire so i took it to the dealers to find the cause. they said it was the #1 fuel injector. since the injectors were hard to reach i replaced all the rear injectors, but not the front. the car ran like a brand new car for about20 minutes and then the same shake returned. the next morning the car was hard to start and seemed to be flooding. when i got it started there was grey smoke that smelled like fuel from exust, put put put sound was coming from the mufler, and this has been the problem since. it has those conditions and the shake worsens when the ac is on. when driving you can smell lots of gas smell coming from the exaust. performance seems to worsen after the car reaches normal temp. the code from the ecm says multiple misfire. when it was only cylinder 1 misfire i drove the car but the shake was annoying, now i can't drive the car and it even misfires when the rpm's are low and i'm driving it. does anyone have a clue what's going on, i will appreciate any response, before i take it back to the stealers

 

I would go with the cheapest solutions first, new spark plugs, air filter, and fuel system cleaner. Also your fuel filter might be bad