Resolved Restricted Performance
#1
Resolved Restricted Performance
For the past couple of years I have been chasing an intermittent Restricted Performance issue that usually popped up when I restarted an already warm engine. It never would throw codes but occasionally would run a touch rough for a moment before settling down. I thought possibly coil pack or throttle body related but it was difficult to troubleshoot.
Last year I finally caught a P0121 TPS and posted this https://www.jaguarforums.com/forum/showthread.php?t=96436
I cleaned the contacts on some cables and made sure the throttle body was all clean in the process but still had occasional issues. I thought I might have to spring for the gold contacts per the TSB but it wasn't bad enough to warrant it yet.
This year after hibernation the problems increased dramatically. Every time I attempted to restart a warm car it would run rough and throw restricted performance. It finally threw the P0175, P0307, and P0357. I was originally going to order a coil pack straight from China but since the problem was getting so bad I didn't want to wait that long and ordered one off eBay.
The car is at 82000 miles and between running rich when cylinder 7 started misfiring, I decided it would be a good time to do plugs as well. I used some Bosch iridiums and was surprised how worn the original plugs were.
It's been a couple of weeks now with the one coil pack replaced and new plugs and no restricted performance, rough running, or any issues. The car runs like a dream and it appears to have picked up a few mpg too. It goes to show how touchy these Denso coil packs really are and how they can be tricky to troubleshoot until they are almost completely dead.
Last year I finally caught a P0121 TPS and posted this https://www.jaguarforums.com/forum/showthread.php?t=96436
I cleaned the contacts on some cables and made sure the throttle body was all clean in the process but still had occasional issues. I thought I might have to spring for the gold contacts per the TSB but it wasn't bad enough to warrant it yet.
This year after hibernation the problems increased dramatically. Every time I attempted to restart a warm car it would run rough and throw restricted performance. It finally threw the P0175, P0307, and P0357. I was originally going to order a coil pack straight from China but since the problem was getting so bad I didn't want to wait that long and ordered one off eBay.
The car is at 82000 miles and between running rich when cylinder 7 started misfiring, I decided it would be a good time to do plugs as well. I used some Bosch iridiums and was surprised how worn the original plugs were.
It's been a couple of weeks now with the one coil pack replaced and new plugs and no restricted performance, rough running, or any issues. The car runs like a dream and it appears to have picked up a few mpg too. It goes to show how touchy these Denso coil packs really are and how they can be tricky to troubleshoot until they are almost completely dead.
Last edited by K.Westra; 04-16-2014 at 09:55 AM.
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