I recentlly replaced the cylinder head on my 87 4runner and I just got it back together, got it timed to 5* btc with the jumper installed. Now it has a slight miss and has a lot of trouble starting, it coughs for a few seconds and then stats up and will sound almost normal, but if I let it run for a few mins. it will start to rev up, then cut out, then rev up and cut out, and it will keep doing that unless I give it some gas. When I get it into high revs it seems to run alright, but when I let of the gas it takes it a while to get back down to idle. I'm guessing I forgot to hook up a vacuum line but I can't find any that I forgot, and it seems like I pluged all of th wires in. anyone have an idea of where to start looking?

 

Now it's giving me a CEL code 21 (oxygen sensor, or o2 sensor heater) could this be related to the problem, I chcked the wiring to the o2 ensor and it looks good.

 

my guides don't show a code 21 for an 87. hmm
on the other hand a code 12 is knock sensor... which may make sense if the timing is too far advanced though....

 

when you jumped the test connector, did the idle speed noticibly change?

 

I don't have guide for a 87, but I have a guide for a 88 and it's showing 21 as being the oxygen sensor. The CEL flashed twice and then, it flashed 1 time, a second later, and showed the code agian after a much longer pause, so I think it's 21 not 12. and the idle did drop when I jumped the connector.

 

I found a vacuum leak and also found a unconnected ground wire that I fixed. It runs better now, but still has a slight miss, untill I press the brakes, then it starts cutting in and out agian.

 

brake booster

 

I replaced the brake booster and that fiixed the problem with the brakes, but when it gets warm it still revs up and then cuts out. I rechecked the timming and when it's still 5* btc, with the jumper, and the idle did drop. it is also is throwing a code 52 now (knock sensor unpluged) but I know I pluged it in. I also tried to find a vacuum leak with propane but I couldn't find one. could the knock sensor or the o2 sensor be causing the problem?

 

anyone? bump