# 91 D21 PICKUP STUMBLING PAST 2k rpm??



## -d21- (Jul 4, 2009)

91 Nissan Pickup 
2.4L 4cyl 
KA24E Engine @ 138k KM on engine and body

Alright, I am getting brain-fckd by my truck right now. Here's the big picture .. (long post-beware!) 

A couple'ish years ago, my timing chain ripped through my side rail and tore a hole into my timing cover ( right into the water jacket ) resulting in a giant Oil/water/coolant orgy. No good. I was strapped for cash then, so fixing it wasn't really gonna happen. 

A couple months ago (just under 2 years after the truck prob occured), I decided to fix this shit up. So.... I stripped the engine down to the block to do a semi-rebuild. I replaced the

- timing chain/tensioner/rail, both sprockets, new front seal
- I got the timing cover welded where the hole was torn,
- replaced the head gasket and all gaskets that I needed for rebuild, 
- New water pump 

As for the rest of the parts, they were thouroughly cleaned, re-lubed and re-assembled. I have the engine back together now .. and after getting a good portion of fine-tuning out of the way ... I am completely SNAGGED on this one problem...

I got my engine idling at about 650, but whenever I give'r accel to go above 2000 rpm... VWOOMBLUAGH ... it stumbles ... comes up ... stumbles down ect ect. Ive seen many other online cases like this, where some of them were a quick fix ( like BPT or EGR valve was stuck or just needed to be cleaned). Not my case ... I have done a compression / fuel pressure / and vacuum test and to no avail. All seem to check out. 

Ive also taken my whole egr system out examined it and cleaned it, as well as blocking it off completely and still no fix. 

As far as codes ... I got some MAF and air temp sensor codes, but I was able to clear all that up and now im getting the good 'ol '55 SYSTEM OK'. 
These codes were from the truck ECU and I also scoped it. 

One thing that just aint right, is how lean my truck is running. It's obviously thinking its too rich when i accelerate because it decides to not inject ENOUGH gas past 2000rpm. Right now my main focus is the MAF and possible o2 sensor, even though i'm getting no codes. 

Anyway, sorry for the long post but the more info the better diagnosis, right? 
if ANYBODY has had similar problems and have found a fix for them (even if its a completely unexpected, stupid fix) I would really appreciate any advice/info/solutions ect. 

Thanks !


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## rogoman (Dec 16, 2004)

Most likely a bad MAF.


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## TripleStripeD21 (Dec 17, 2009)

*If you haven't already fixed it*

I had almost the exact same problem on my 1993 d21, Apparently some mice got to all my sensors on my throttle body, i just replaced the whole unit and never had a problem since.:givebeer:


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