QuestionQUESTION: First of all THANK YOU! I have been trying to get you a note for at least a month now, and am please that I have the opportunity now and very grateful for your time once again, as well as your dedication to this site! So here goes...it’s a 1989 Nissan Pathfinder SE 3.0, 4 wheel drive, and automatic transmission:
I just put in a new manifold gasket on driver side, and a new fuel pump. I also just had a wire get caught on the AC and it blew the fuse and I replaced the pressure cut off switch because it was that wire. (AC works fine now.)
The car is running rough during morning start up, and has a difficult time powering up (or getting any speed) after it starts and it takes a lot of down shifting to get the car up to speed. I start in 2 than move up to 1 than to D with the power button on in order to get the vehicle up to speed. During zero to moving acceleration it almost stalls with the AC on so if I cut it off I get better power till I get up to speed. it does have a tough time even with the ac off too....
Also while running on the highway, after keeping power in by using low gears and up shifting to keep speed increasing…. When I get to drive, with the Power button turned off, sometimes the RPM increase a couple thousand and I need to let up off the gas to get it back in gear. It seems like the engine and transmission “separate” and I need to reduce the throttle in order to get power back. Also it runs in very high rpms 4000+ but no speed above 60mph
I have cleaned the connections on the throttle sensor and the air flow meter, as well as the cam sensor in the distributor, and have gotten what seem to get a little better performance from her, but still not running normal. I know she can use a tune up as well….but do you have any additional thoughts on this?
ANSWER: Michael,
I would check to make sure the converter on the exhaust is not melted and plugged up. Yes, a complete tune up would be in order like new plugs, cap, rotor, wires and filters. You can take the converter down and look into the inlet to see if the material is melted and deformed. If it is replace the converter. You need to check the basics like timing and fuel pressure. I first say converter because the way the vehicle is acting. You did not say if the vehicle was running the same way before you did the manifold? If there was an exhaust leak for a time the oxygen sensor will think the engine is lean and run the fuel mixture rich to compensate and this extra gas will melt the converter. Email me back with what you find. Also, are there any codes present? And, I do not think the transmission is messing up.
---------- FOLLOW-UP ----------
QUESTION: sorry for the additional question :-)
How do I check codes on my 1989 Nissan pathfinder? I went to autozone but they said the car had to be 98 or newer.I know ..basic but I didn't know I had this opportunity...
I will be doing all the work above on Sunday and will let you know what I find.
sincerely,
MM
AnswerMM,
The computer will only read the codes on a 1996 or newer. On your 1989 you can read the codes by using a screwdriver on the computer. There is a light you read the morse code from. If you have a Hanyes Manual for your vehicle it explains the codes and how to read them.
