Greetings folks,
I have a quick question I think you can help me with. I have a '90 300NA with 38,000 miles. It seems sluggish when I start out but fine at 2500+ RPM. I have new platinun plugs, cat back and replacement K7N filters...Could the plugs be the problem?

 

there could be many problems...if i could find the previous threads id show them to you...ill go look

what brand, type of plugs did you get

 

Bosh platinum+4

 

First .....I'd say your odometer broke about 10 years ago.

Then I'd say start checking vaccum lines and stuff ........ ECU codes.....
Does it idle o.k.?

 

The milage is actual miles, I bought it with 8000 on it and have had it since.
The idle is smooth. That's a good idea to check for leaks, there may be cracks in the lines. I was looking at the owners manual for the ECU codes and how to check them...it may not be as hard to check as I thought. Thanks

 

Get rid of the Bosch +4's and replace them with the NGK's that are supposed to be in there. When was the last time you changed the fuel filter? A grounding net would be a good idea too. Just for kicks, what grade oil do you use? Do you have a POP charger, or do you have the K&N filters that drop into the stock air box?

 

I changed the fuel filter in May, with the plugs and the drop in K&N filters. I use Castrol 10-30 with nippon oil filter. What is thie grounding net? The car is stored quite a bit and I will use stabil in the fuel to keep the gas in good shape.

 

http://www.ttzd.com/tech/groundnettech.html

Become familiar with Rizzspeed's link page.
https://www.zdriver.com/showthread.php?t=8434

I'm not sure how that stabil stuff works in these cars. That could possibly a problem, but I don't know enough about it.

 

Thanks for the info. I'm going to swap plugs, add the grounding wires and check for vacume leaks this weekend. I hope that will take care of the problem. I think I also need to drive it more than I do...