surging at stoplights and power loss at cruising speed.

[gordsgn]

i have a problem with my stock 86 gn which i have owned for 2 weeks. the problems just started the other day. sometimes as i am slowing down to a stop (ex. at a red light) from cruising speed (60 km/h) the rpms will suddenly rise and the car will surge. this rpm increase will sometimes remain until after i am stopped but usually settles down after a few seconds. the same thing will also happen at a complete stop. i noticed that, after startup, sometimes the rpms will fluctuate. i dont know if this is linked but the problem started during a heavy rain storm and persisted after the rain stopped. thats the first issue.

next. this problem also just started a couple days ago before the previous problem. the car will run fine (except for the aformentioned issue) until i have been driving for approx half an hour. after this the car is still ok as i am accelerating at a normal relaxed pace until i shift into 3rd (around 45 km/h and any speed higher) where it seems switch between losing power and surging. usually at any point when this is happening if i try to accelerate at about half throttle the engine will lag but eventually regain power and accelerate. i am thinking maybe a fuel pump issue (it gets 'tired' after extended use) as it takes a while for the pump to build pressure when i turn the key on and it takes a few seconds of cranking until the car actually starts.

the only thing that i have done is clean the k&n (the problem started after this)

i dont have a lot of knowledge about these cars as i am a new owner and i dont have a scantool or anything like that yet

any ideas...?

 

[Turbo1dr]

Start fresh. Check the fuel filter, spark plugs, plug wires and vacuum hoses for any leaks along with intercooler hoses. Pull the computer down and check what type of computer chip you have in there.

Check fuel pressure with the vacuum hose removed from the regulator.

With the engine running at 2000 rpm in PARK tap on the mass air flow sensor and see if the engine 'stumbles'. This is just a check as it might not be a problem.

You can check the TPS setting with a digital/volt/Ohm meter set on 5V scale if you don't have access to a scan tool. .44 to .46v is what I like at closed throttle and 4.50v or above at wide open throttle.

Clean the throttle body butterfly and around on the inside of it where it touches.

Is the CHECK ENGINE light on? If so check the codes first. That's always where I start. if the light is on.

 

[SlickTR]

First thing I would do is check the MAF...you may have gotten oil on it from the K&N after you cleaned it...If this is not the issue it sounds very similar to what my car did and it ended up being the Cam sensor cap.

 

[gordsgn]

where is the fuel filter on these cars. i did a quick check because i too thought that this might have been the problem but i didnt see it. is it on the frame?

 

[TR Custom Parts]

Drivers side frame to the front of the rear wheel. Take care not to twist the fuel line when removing.