Power cutting out while driving

[horsepower]

Well i have a 91 nissan 240 sx :ylsuper This is odd to a degree to me cause when driveing and holding 3000rpm with air off you can feel the power cutting out. It will do it for like 2 to 3 sec and back to normal. Then repeat ! Altinator is new and replaced belt to it also,and a new set of plugs. no smoke from tail pipe and no engin noise. Put injection cleaner in fuel 3 times changed air filter had battery checked also. My brain is to its limit here any info is good info. Could it be wireing ? Let me add it can be any rpm that loses power and its like very little power like 10% for a few seconds:help

[JNM240]

Have you cleaned out your throttle body? Get some carb cleaner and spray the $^!% out of it. Also, check your coolant temp sensor. If it is not making good contact, it could tell your ECU that your engine is cold, which would dump a lot of gas in and make it hesitate (although this would make it burn black smoke, if it does it intermittently you may not notice the smoke). One stupid this is to check your rotor and dist cap, and make double certain that all your plug wires are seated well. Hope this helped a little!

[horsepower]

I dont know much about nissan the coolent temp senser i have found and going to replace Sat. but the throttle body i have no idea. like take it apart .Or spray the out side of it or spray it in the intake. i know i sound dumn thats cause iam when it comes to nissans iam but i want to learn. I have a dream for this car and going to go threw with it. Could you explain the throttle body in just a wee hair more detail plz. Thanks Again

[JNM240]

Follow the intake hose from your air filter box all the way to the left side of the engine. Where it connects to metal, that should be your throttle body. Pull the intake hose off of it (usually need to remove the clamp and some other minor stuff) and check your butterfly plate. It should be bright and clean. If not, spray the crap out of it with Carb and Choke cleaner. Open the throttle body by hand (using the throttle linkage on the right side of it) and spray some directly into the throttle itself. If black gunk pours out, keep at it till it stops. You wont be able to run your car with the intake hose off of the throttle body (your MAF sensor is near the air filter, so the ECU will see that no air is coming thru and wont put any gas in the mix, therefor wont run), so put it all back together and start it up and rev the crap out of it for a few minutes.BTW: What did your coolant temp sensor look like? Was it all nasty green corrosion? Did you check the pigtail connector that plugs into it? Was that all green with corrosion? If so, that needs to be replaced also. Nissan doesnt sell the connector by itself (only part of the entire engine harness for about $1000) so go to a junkyard and pull on off another 240SX. Doesnt even have to be the same year of from the same location. Any 2 wire pigtail with the same connection will do. Solder the wires together (otherwise nothing will have changed) and use some dielectic grease (the stuff you use on spark plugs & wires to prevent corrosion) inside the connector. Hope this helps!

[horsepower]

Ok i royaly cleaned out the throttle body . Cleaned 3 times like you said black smoke from hell fire filled the air.But there is still black junk in side of there put a wrench in a white rag in there after i cleaned it and there is still loads of black stuff in there.Should i take the throttle body apart and clean it real good. As far as the sensers go i took both out and cleaned them.But i have had an over heating prb. too. Had a new raditor put in last year and thromostat but after i cleaned the senser. Startred my car and it heats up all the way to hot.Should i replace the senser and or replace the thermostat. Could it be an eletric prb. And should i take the throttle body apart and clean it. When i smash the gas to the floor the power drops so much it jerks my head forward then the power picks up .My car dont responed to good till 5grand.Only 100k on motor But since i clean the throttle body some its a little better.Think i need to advance the timeing if so how is that done i know how on a regular distribter cap. I belive this nissan is diff tho I really appricate your time in helping me out and reading my grammer.( altho its bad! lmao) And just may be power wise with my car iam expecting to much at get go. And the was no green on the senser or conectors Still looked new no corosion at all i wash the engin often

[JNM240]

Well unfortunately its not just going to be the throttle body. If u pull that, u may as well pull the entire intake manifold (not recomended, its a chore and a half). Only things i can suggest is to get new plugs, wires, ect ect and use the best gas u can find. Expect a little lag when u smash the gas, theres actually like a 1/4 second delay built into the stock ECU. Im not sure u want to advance the timing with it running poor like this, it might do more harm than good. One last thing to check might your fuel filter. If its clogged, it may affect performance.Thats good that your coolant temp sensor connectors were not corroded, i would still (and do myself) put some dielectic grease on them just to make DAMN certain they do get that way. AS for you overheating like that, dumb question, you got enough radiator fluid in it? Ive never had an overheating problem (except after i put my Nismo cam in when it idled so rough i thought it was gonna tear my motor out the engine bay), so i really cant help with that much.

[horsepower]

Ok Bro. Thanks for al the help again.And ill wait on the intake till i get a new one(will be a little while). And all the stuff you had me do is really help my car alot . Your give good info. Peace

[drjohn]

The first problem of loosing power a few sec. at a time sounds as if the egr port or ports are clogged in the int.man.and at steady speeds it dumps to much egr in one cylinder and causes a lean misfire. This can be checked by taking the vac. hose off egr valve and driving. This may cause a eng. check light to come on. The falling on it's face after cleaning or removing the sensors on the throttle body is more like the tps sensor out of adjustment and it runs good at 5'g because you are on full throttle. The over heating sounds like possible air trapped in coolant system if you had any coolant hoses off or just a shorted wire or sender.

[horsepower]

Ok DR.JOHN ill check those. and thanks DOC ill post the out come.

[horsepower]

Ok doc i belive i found the egr valve .I followed the exhaust hose to the intake. and above it was a valve.It didnt have egr wrote on it tho had some other letters and numbers.But removed the vac hose from it and there was no changes at all. I done a search on the TPS senser cant find any info on it and i dont know what TPS stands for.Doc i didnt remove any throttle bode sensers at all those sensers where coolent sensers.Only thing i done too the intake was spray some STP in it to clean it some.What do i do about the egr valve and the tps now. Cause iam a newbie totaly lost here. Thanks again

[JNM240]

Not that this will help at all but:EGR = Exhaust Gas RecirculationTPS = Throttle Position Sensor

[horsepower]

i am going to have to take it to the shop i guess i dont know where the EGR and TPS are at i looked for the letters on the parts wish i knew what the hell fire i was doing...

[JNM240]

EGR valve: there is a hard metal line coming off of your exhaust manifold that goes around the backside of the engine to the left side. Follow this hard line and you will run into the EGR valve. What this does is it recycles burnt exhaust gasses into your intake stream. If this valve is clogged up with carbon deposits, it will not operate properly. I had to change mine a few years back, it was a b!^ch to get to, i wound up most of the time under the car with the starter and, if i remember correct, the alternato off. To check for proper operation, warm the engine up and place your finger on the underside of the 'mushroom' shaped top. This is the diaphram. While idling, push gently on the diaphram, you are in essence closing it. You should notice a definate difference in idle (should get worse). If not, you may need to clean the EGR.TPS: This is located immediately to the right and hanging off of your throttle body. This works by inputing to the computer the angle of your butterfly (inside the throttle), thereby telling the ECU how much u r stepping on the gas. Unfortunately i dont how to check this. You probably need a multimeter or something, but i havent worked on this item (yet...). Dont despair, cars arent easy, ive been around em most of my life (mine always seemed to break down), and yet i dont deal with em for a living. Wonder why. LOL

PS If Nissan were thoughtful they wouldve labeled each and every component on the car, but they didnt, so you will almost certainly NEVER find the item you are looking for by looking for its name on it. I have a SOHC, but if u need me to i can email u some pics of where the EGR and TPS are. They might be slightly different if u have a DOHC.

[horsepower]

I massaged that EGR valve and the car died when i push the diafram wow thats a easy way to check it. Is there any other reasons to why the power cuts out?

Guys thanks for all the info this is better than going to a nissan mec school. Thank you all :ylsuper

[davidfrost240]

My car would bog down immediatly after shifting, but after that it seemed fine. I had the same kind of jerk you were talking about too. Here are the things I did. I cleaned the AIV (air induction valve), this helped a little. Then I also changed the oxygen sesor, and that totaly fixed the bogging problem. Note: it only bogged immediately after shifting the majority of the time.

David