i put my new engine in and i have a miss.

[saul a 91 sport]

well i got the engine from a 93 explorer put into my 91 and it runs good but it will stutter when the gas is pressed down really fast. as the vehicle warms up it doesnt help any. also when i am in fourth gear and i give it gas it bogs and bucks like crazy. the thing just misses at idle when it is hot. it seems like it runs alot better when i get the rpms up above 1000 but around 700-800 it is ****ty. any advice would be appreciated

 

[ExploreMinnesota]

The idle problems you describe sound like a vacuume or some other intake air leak.

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ExploreMinnesota
91 EB 4x4 Stock

 

[rockylaurence]

Did all the emissions from the new engine hook up to the old system? I'm not sure, but I think there are some differnces between the years (91 had only 1 o2 sensor etc). I'd take it into the dealer and have them check it. They should be able to track-it down quickly. How did the install go?

 

[saul a 91 sport]

the install went good , we used the plenum from the 91 and bolted it to the base on the 93 for the sensors to work. it gets worse when the engine gets warmer could that shed any light on the problem. also it isnt bad if i get it up in the high rpms.

 

[rockylaurence]

It sounds more like a vaacum problem. However, if the problem is worst when accellerating (under load) it may be the timing module--it may not be advancing the timing as needed. The crank trigger didn't get bent out of position did it during the install? Also, check all your plug wires and plugs.

 

[saul a 91 sport]

well the explorer exactly does this.
it idles rough when under 1000 rpm.
under load it misses or bogs and lurches.
it does all this more often when it is hot under the hood. i put new wires on and no help. could it be the ignition where the plug wires plug into? i have checked for vacume leaks and that is a possibility but it feels like an ignition problem because it is backfiring at times under load. if you know what this is yuou are a genious

 

[rockylaurence]

Saul; did you get it going?

 

[Paul Gagnon]

sounds to me like you have your wires crossed. Dead Link Removed Check you spark plug wires to make sure that they are going to the correct cylinder. If they are not then you will get the symptoms that you are seeing.

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Paul Gagnon
Calgary, Alberta
"No Brain, No Pain"
Dead Link Removed

Technically Velveeta isn't REALLY cheese... it's a cheese food...
The stuff that other cheeses eat... I guess.

 

[wlm66]

saul,
I have a very similar problem -- rough idle, bogging, lurching, some backfires under load. Only difference is that I have my original engine. Mine is a 1992. Any other ideas anybody?

 

[saul a 91 sport]

i was correct on my initial suspician a cracked plug is all it was. the wires were brand new and i checked them when i put them on so i ruled that out but it is good advice. plugs which are cracked will really act up due to all of the voltage on the exp