86 misses at 1500 rpm ??

zimmy · 02-15-2011, 03:05 PM

Hi all. I have a bone stock 1986.5 with the 7MGE,automatic. Driving threw town at 1500 rpm the engine will drop to 1000 rpm for a second then go right back up. It does not do this at any other rpm. It will do it maybe once in two blocks. Runs great other than that though, Any ideas as to where to start looking ?

spunkenhimer · 02-16-2011, 05:40 AM

Hi mine is doing that at 2000rpm and I believe it is due to timing and vacuum lines. haven't actually fixed the problem yet but i'd check your compression as well as your vacuum lines make sure you don't have a leak.

zimmy · 02-16-2011, 11:59 AM

Compression is good total engine rebuild 20,000 miles ago. Guess I will check for vac. leak next. Thanks

cre · 02-17-2011, 02:29 AM

Test the ISCV and TPS. Recalibrate the TPS too. You have checked for diagnostic codes, right?

02-15-2011, 03:05 PM	#1
zimmy Stock Join Date: Jan 2011 Location: pa Posts: 11	86 misses at 1500 rpm ?? Hi all. I have a bone stock 1986.5 with the 7MGE,automatic. Driving threw town at 1500 rpm the engine will drop to 1000 rpm for a second then go right back up. It does not do this at any other rpm. It will do it maybe once in two blocks. Runs great other than that though, Any ideas as to where to start looking ?

02-17-2011, 02:29 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Test the ISCV and TPS. Recalibrate the TPS too. You have checked for diagnostic codes, right? __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

02-16-2011, 05:40 AM	#2
spunkenhimer Intake Join Date: Feb 2008 Location: Pikeville NC. Posts: 49	Hi mine is doing that at 2000rpm and I believe it is due to timing and vacuum lines. haven't actually fixed the problem yet but i'd check your compression as well as your vacuum lines make sure you don't have a leak.

02-16-2011, 11:59 AM	#3
zimmy Stock Join Date: Jan 2011 Location: pa Posts: 11	Compression is good total engine rebuild 20,000 miles ago. Guess I will check for vac. leak next. Thanks